Not too much to worry about with the neighbors having bees as well. I have not found the saturation density for bees in a urban setting yet. I am in the middle of Lexington, KY (300,000 + population) with 6 very strong hives in my yard, my neighbor has 4 more, three doors down has 5 more and I know of 3 more feral colonies in tree within a 2 block radius. No ill effects yet. Hope you enjoy your bees as much as I do.