These are, in chronological order, the earliest occurrences of to treat with ignore that I have found:
1-: From Catty Communications, by ‘Kitten’, published in Smith’s Weekly (Sydney, New South Wales) of Saturday 21st September 1935:
With such strict enforcement of the liquor laws, my dear, parties these days can become quite unpleasant affairs. For instance I went to one the other night for a very charming little lady, and quite half of the men present, no less than four, in fact, were out on bail. There was even a type of class distinction growing up among them, too, for the man with only £10 bail to his name was simply treated with ignore by his more stylish friends with £100 to their credit.
2-: From a letter to the Editor, about the Art Section of the Kiama Show, published in The Kiama Reporter (Kiama, New South Wales) of Wednesday 13th November 1935:
The humble pen-and-ink person is “treated with ignore” altogether.
3-: From Business, Robbery, Etc., published in The Bulletin (Sydney, New South Wales) of Wednesday 6th July 1938:
The Distant View
The manner in which Australian sharemarkets are influenced by the humors of the American and London Stock Exchanges is something that passeth all understanding. The world prices of wool and wheat are matters real to us; the level of world interest rates is real; the political “situations” of various other countries are sometimes of real importance to our own economics. But why we should be enslaved to the Dow-Jones and “Financial Times” share-price indexes is a first-class puzzle. It all tends to make us believe that the habit credited to Australians of gambling on flies crawling up a wall has ceased to be a joke and has become a national instinct.
For many months our own indexes of prices, progress and profits have been utterly ignored by sharemarket followers. Broken Hill Prop.’s output figures have had less to do with prices for B.H.P. shares than have output figures of United States Steel. That is no exaggeration, U.S. Steel being such an important factor in the “tone” of American markets of many kinds. The announcement last week that steel was to be cut in price in the U.S.A. in order to encourage consumption of the product in the motor-car and building industries was given more prominence in Australia than B.H.P.’s record production figures for 1937-38.
This habit of “treating with ignore” our own industrial experience is quite wrong. Apparently sharemarkets must have their ups and downs, and any old excuse is good enough for beating a dog—or tying a ribbon round his neck. In this country our industrial outputs generally have either been very stable or have shown a tendency to increase—nothing startling either way. And though the trade balance, export price level and taxation position recently influenced a sharp decline in share prices, the Dow-Jones index of New York prices soon encouraged a steep recovery. A vacillating position.
4-: From Right Off The Track: Or, A-punting He Will Go, by Gordon Williams, published in The Argus (Melbourne, Victoria) of Wednesday 22nd February 1939:
Yesterday I attend my friend Mr. Doncaster to a well-known racecourse to watch all the horses practising up different ways for me to do my money on them […].
Well, what next is it I see but the hurdle school. You could tell it was a hurdle school a mile off, on account of there is a man who is holding up his hand, and the teacher don’t see him, on the which I protests to Mr Doncaster.
“He is acting as starter,” he told me, but I don’t get this, as this chap could of started himself instead of holding up his hand for five minutes and getting treated with ignore. I tell this out loud, and then something happened to me.
I came to with the noise of sweet music like the Bridle March pealing from a near by steeple.
It has erroneously been said that the phrase to treat with ignore originated in army slang during the Second World War. The following, for example, is from Diggers Add To Dictionary, by John Quinn, published in The Sun (Sydney, New South Wales) of Wednesday 26th August 1942—here, the noun digger designates a private soldier:
In one battery, if a man was overruled he was “treated with ignore.”