The phrase to be skating on, or over, thin ice means: to court danger by behaving in an obviously risky manner that cannot be sustained for long.

This phrase occurs, for example, in the following from A powerful apparition, by Andrew English, published in The Daily Telegraph (London, England) of Saturday 5^th October 2013 [No. 49,255, page M 10, column 1]:

Elegant skating over the ice is just a normal day for a Rolls-Royce PR. No more so than on the subject of its new coupé, the Wraith. Calling a car after a ghostly portent of one’s own death is perhaps not the best way to charm safety authorities. And there’s more skating over the historical allusions to the last Rolls-Royce Wraith, the 25/30 of 1938, which was far from the best Rolls-Royce ever built, at the end of a series of some of the worst.

The earliest figurative uses of the phrase to be skating on, or over, thin ice that I have found are as follows, in chronological order:

1-: From Essay VII. Prudence, in Essays (London: James Fraser, 1841), by the U.S. poet, essayist and philosopher Ralph Waldo Emerson (1803-1882) [page 237]:

The eye of prudence may never shut. Iron, if kept at the ironmonger’s, will rust. Beer, if not brewed in the right state of the atmosphere, will sour. Timber of ships will rot at sea, or, if laid up high and dry, will strain, warp, and dry-rot. Money, if kept by us, yields no rent, and is liable to loss; if invested, is liable to depreciation of the particular kind of stock. Strike, says the smith; the iron is white. Keep the rake, says the haymaker, as nigh the scythe as you can, and the cart as nigh the rake. Our Yankee trade is reputed to be very much on the extreme of this prudence. It saves itself by its activity. It takes bank notes—good, bad, clean, ragged, and saves itself by the speed with which it passes them off. Iron cannot rust, nor beer sour, nor timber rot, nor calicoes go out of fashion, nor money-stocks depreciate, in the few swift moments which the Yankee suffers any one of them to remain in his possession. In skating over thin ice, our safety is in our speed.

2-: From Protest, against the action of the General Synod of the Reformed Presbyterian Church, in the case of the Pittsburgh Presbytery, at Xenia, May, 1850. By William Wilson, A. M., Pastor of the Church of the Covenanters, in the City of Cincinnati (Cincinnati: Ben Franklin, 1850) [page 53]:

The clerk, with the most indecent haste, while Dr. Heron was on the floor to propose his substitute, commenced calling the roll; and the Moderator decided, in answer to cries from all parts of the house, “Moderator, what are we voting for? How much does this comprehend?” that the question now before the house was, “sustain or not sustain the complaint of Mr. Black!” With regard to the other inquiry, however, as to how much it comprehended, the worthy Moderator, who would never do this business for himself, and whose fault is that he is not his own in such cases, but the too pliable instrument of his friends and relations, knows not himself. And the clerks withhold from him the usual aid of their prompting and dictation: for they know that the less that is said about what they are now doing, it will be the better; and that in skating over thin ice, the safety is in speed. He is silent and puzzled. The clerk persists. “Mr. ——, how do you vote? Yes or No?” “Well, Yes.” Thus, it is sustained by a majority of such affirmative responses.

3-: From Marriage Settlements, published in The Saturday Review of Politics, Literature, Science, and Art (London, England) of Saturday 6^th April 1861 [Vol. XI, No. 284, page 336, column 2]:

There was a time—at least so the poets and our own youthful recollections tell us—when love-making had something of the excitement of a chase. But now it is Daphne that runs after Apollo. Hunting would be very poor fun if the fox were to meet the hounds half-way—or rather, if the fox were to chase the hounds madly over hedge and ditch, imploring them to eat him. Whatever the explanation, the consentient groans of countless dowagers attest the fact that the men will not propose. Celibacy is receiving year by year into its cold and cheerless solitudes numbers of willing, waiting, but alas! groomless brides. The effects of this famine of husbands are horrible and heartrending. […] The most innocent portion of the imitativeness which Juvenal ascribes to the wife of Claudius is becoming fashionable among English young ladies. An inverted hypocrisy is the homage which virtue now pays to vice. Sterling silver, it is found, cannot be sold without an electro-plate of very different metal. The Haymarket gives the law of tone, dress, manner, to Rotten-row. In that aristocratic retreat the reign of universal reconciliation is being foreshadowed. The sucking child plays on the hole of the asp, and the weaned child puts her hand on the cockatrice’s den, in the full confidence that they shall not hurt nor destroy. And the semi-acquaintance results in a loan of weapons. A species of poaching is now only too common in the matrimonial chase. The legitimate sportswoman no longer brings down her game in the old fashion, but borrows the snares and gins of her less recognised sister. In fact, the old weapons are thought to have failed, and the others are known in their own sphere to have succeeded. To vary the metaphor, skating over thin ice is a favourite maidenly accomplishment of the present day. So at least, in far blunter terms, it has been averred by a contemporary, qualified beyond all others to reveal to the outer world the secrets of fashion. Whether the full-blown Messalina will make her appearance among her partial imitators, whether the thin ice will not give way beneath some of the less nimble feet, remains to be seen. If Paterfamilias is not ambitious for such results, he had better open his eyes. There is no doubt that the evil is both grave and growing.

4-: From Skating on Thin Ice (London: T. C. Newby, 1863), a novel by the British author Septimus Berdmore (1829-1906), in which Mrs. Beaumont, a woman of essentially bad character, is determined to effect the ruin of the hero, on account of his neglect of her amorous advances—the following is from the review of this novel, published in The Observer (London, England) of Sunday 26^th July 1863 [page 7, column 5]—the obsolete noun horse-breaker, frequently pretty horse-breaker, designated a courtesan, a demi-mondaine; pourtray is a variant of portray:

The title of the book seems to be derived from the introduction of several young lady characters, pretty horse-breakers as they are now called, who flutter from flower to flower, or skate upon thin ice, and occasionally “put their foot in it.” There is some excellent advice to young men, who are cautioned to avoid any liaison with these fragile creatures. The character of a cold-blooded beauty, with an admixture of Italian blood in her veins, is well pourtrayed, and is calculated to instil caution into those of the sterner sex who may have any very soft places in their hearts.

5-: From Heir Hunting, published in The Saturday Review of Politics, Literature, Science, and Art (London, England) of Saturday 30^th May 1863 [Vol. XV, No. 396, page 691, column 1]—the following is about the elder sons and “all who are in any degree worth being hunted down”:

Refined female society they will, as a rule, have, though they cannot have it in the conversation of young ladies, the greater number of whom are brought up to look on them with a purely commercial eye. The demand from such a quarter is pretty sure to create a supply; and as the young unmarried ladies are shut out by the manœuvres of their mothers, it must be furnished by those who have removed that disqualification. Snake-charming is a perilous amusement except with snakes whose fangs are drawn. The arrangement is, no doubt, a very pleasant one for the young men. Married women are in themselves more practised, and, therefore, more agreeable talkers than young ladies; and even if they were not, a friendship which does not lead up to a question about intentions is necessarily a very much pleasanter and more comfortable kind of intimacy than one that does. But it is not to be expected that the prevalence of such a state of things should be free from consequences of a more serious kind upon the morality and the repute of the classes among whom it exists. For the present, the game appears to go on merrily. Skating on thin ice is a delightful amusement until the ice breaks—and, perhaps, for some time after. But if the pastime should result in extensive scandal, no small share of the blame will belong to the dowager-system, and especially to the vigorous practitioners who have pushed it to such a length in our day.

6-: From an article about the rule of Napoléon III ¹, published in The Globe and Traveller (London, England) of Saturday 6^th June 1863 [No. 20,251, page 2, column 3]:

He [i.e., Napoléon III] has never scrupled to devise and enforce the most severe laws; he has known how to permit a species of liberty under these laws; he has placed the press in a position in which it may “snatch a fearful joy” from that sort of free discussion which is like skating on thin ice, and he has even permitted his elected deputies to talk upon public affairs, subject to the discretion of the Duke of Morny ².

¹ Charles Louis Napoléon Bonaparte (1808-1873) reigned as Napoléon III, Emperor of the French, from 1852 to 1870.
² Charles de Morny (1811-1865) was the then President of the Corps législatif.