1836 29 July (headline) School treat... The boys..were plentifully regaled with fruit, tea and cake, in a field adjoining the vicarage.
1934 D. L. Sayers 121 An importunate child at a school treat.
2007 D. J. Taylor (2010) xi. 280 I think it's obscene to see a lot of middle-aged men and women behaving like children at a school treat.