I’ve done Halloween for the first time in the uk with my 2 year old, and we passed a few lightly decorated doors (apartment block). Most other flats had a bowl of candy outside and is this one not having it, we were not sure if we could knock or not. I found myself thinking that they were out or didn’t want to be bothered. It has become very unclear. I think next year even if I’m at home (before we go trick or treating) I will put a sign on the door if I want them to knock, so I make it clear to all.