I wasn't allowed to go trick-or-treating when I was young. My mother flipped between two justifications for this: 'It's begging' or 'You're threatening to do something if they don't give you something'.
I think there is more etiquette involved now. Only houses with decorations get hit, and people make an effort with costumes. In the mid-90s it was just kids with a box of eggs and some toilet paper.