We live in the country, so we go with my SIL to trick or treat in her neighborhood. It's a neighborhood with a ton of younger families, so there are tons of trick or treaters. The rule here is that if your light is on, trick or treaters can knock. I'd say about 50% of houses participate.
I also helped hand out candy at her place, and was a bit disappointed by the number of kids that either had no manners, or older kids that put absolutely no effort into a costume other than throwing on their H.S. jersey. For every cute kid, there was another who marched up to the door and just said "how many pieces of candy can I have?" No "trick or treat", no "thank you". Then there are the parents that drive their kids from house to house. Seriously. That's not how I'm raising my kids, but I can see after a couple years of that how one could lose interest in handing out candy.