Question: In what year did the first known reference to ‘Trick-Or-Treating appear?
Answer: 1927 in a Southern Alberta newspaper.
https://www.cbc.ca/news/canada/calgary/albertans-invent-saying-trick-or-treat-1.3829669
https://www.history.com/news/halloween-trick-or-treating-origins
https://www.thesun.co.uk/fabulous/4609024/trick-or-treat-halloween-origins-2018/