its a goo idea because I have seen kids out for hours and hours going trick or treating knocking on peoples doors. its good because people are not out too late.

They never had that when I was a kid, but it seems like a pretty good idea.
We used to just go from about seven or eight at night until about ten.
It was good exercise actually, considering that we never got much candy for the amount of walking we did. xD

6-8pm after that is to late at night

As far as I know, we don't have set hours. That said, I only hand out candy from 5pm after work till around 8pm. After that, the lights go out, and I relax.

I've only see it at community centers, malls, etc.