Green’s Dictionary of Slang

an outing, a visit to a restaurant etc, in which costs are shared equally, i.e. there is no ‘treat’ at all in the sense of one party being entertained at the other’s expense; occas. as v.; also attrib.

1877		N.Y. Times 18 Mar. 6: The expense of any kind of feast, it is supposed, must be borne by some person. It is true that there are ways by means of which this sentiment may be got around. But a certain sordid character still hangs to that transaction, which has been dubbed a ‘Dutch treat.’.
1887		Lippincott’s Monthly Mag. (Phila.) Aug. 191: You’ll come along too, won’t you? [...] Dutch treat, vous savez! [F&H].
1902		Ade Girl Proposition 99: All they expected was a little ’Coon Stuff on the Piano and then some Dutch Lunch.
1914		Ade ‘The New Fable of the Speedy Sprite’ in Ade’s Fables 25: The usual Battle as to which should pick up the Check and the same old Compromise. A Dutch Treat with Waitress trying to spread it four ways.
1919		Van Loan ‘IOU’ in Score by Innings (2004) 355: We can Dutch-treat the ride, so’t nobody will be hurt.
1926		Maines & Grant Wise-crack Dict. 7/2: Dutch treat – The way two girls take each other to lunch.
1930		R. Whitfield Green Ice (1988) 185: Eat with me – dutch treat.
1948		Daily Ardmoreite 12 May 2/5: Carter County Oil Men’s association will stage a dutch lunch meeting at Lake Murray state park Thursday night [DA].
1949		Chicago Daily News 8 Jan. [caption] 13/2: [They] were part of Dutch treat crowd that took dinner at Fortnightly club [DA].
1949		F. Brown Dead Ringer 104: And Dutch treat. I’ll buy the next round.
1950		‘Neville Shute’ Town Like Alice 225: But look, Joe – this is to be Dutch treat [...] I mean you pay the boat one way and I’ll pay it the other.
1959		Mad mag. Oct. 33: A teenage boy investigates the possibility of mutual funds, which means getting the girl to go ‘Dutch treat’.
1960, 1975		Wentworth & Flexner DAS.
1978		R. De Christoforo Grease 117: My Dutch-treat days are over.
1979		Maledicta III:2 158: Dutch lunch; Dutch party; Dutch supper; Dutch treat n [DA 1904] One after which each pays his own bill; from the alleged Dutch parsimony.