One or two suggestions that the event has been imported from the US to the UK in recent decades. Isn't so. In Scotland there has only really been a change in what was an existing thing. As kids in the early to mid 60s we called it 'guising' as my parents did before us. Since about the time that E.T came out kids tend to often call it trick or treating but it remains the same thing. They get dressed up, go round some doors, tell a joke or recite a poem etc, then get a treat. We used to use turnips where pumpkins are used now. Not so much dooking for apples etc as there used to be but still goes on here in the Borders anyway.

We got none this year but our kids are 17 and 19 now. Small groups of kids will often tend to pick the doors where one of them knows someone. Often because in earlier years it was one of the doors where their mum or dad would take them when they were too wee to go themselves. In other words they'll often knock on the doors where they know they are going to be welcomed.