I'll bet central mailrooms are a big driver for safety. In my NYC building, for example, the mailman does not even see any of the public space -- they enter the

I'll bet central mailrooms are a big driver for safety. In my NYC building, for example, the mailman does not even see any of the public space -- they enter the delivery room through the mailboxes' rear side and deliver en masse to all 110+ units' mailboxes. I imagine the higher the highrise the more efficient the delivery and the safer the delivery. Now contrast that to crossing lawns individually house by house...