I live in a neighborhood that is filled with people who use what ever legal stuff you can purchase at Lowe's. Yes, I do know that some people around her use spray round up for weeds.
I know almost everyone uses the big bags of lawn fertilizer and pesticides and some people have their lawns maintained with what ever the professional landscapers use and then put the little caution flags out on the perimeters.
I'm sure this is the case in most neighborhoods though.