Probably better that my kids yell 'Trick or Treat' given that Blackie is where we go on Halloween.
From Wikipedia:
While the first reference to "guising" in North America occurs in 1911, another reference to ritual begging on Halloween appears, place unknown, in 1915, with a third reference in Chicago in 1920.[23]
The earliest known use in print of the term "trick or treat" appears in 1927, from Blackie, Alberta:
Hallowe’en provided an opportunity for real strenuous fun. No real damage was done except to the temper of some who had to hunt for wagon wheels, gates, wagons, barrels, etc., much of which decorated the front street. The youthful tormentors were at back door and front demanding edible plunder by the word “trick or treat” to which the inmates gladly responded and sent the robbers away rejoicing.[24]
https://en.m.wikipedia.org/wiki/Trick-or-treating