Might be worth your while to go visit with the new neighbors face-to-face and tell them exactly what you've told us here.  You've got a very valid point, and I wouldn't think anyone would get their back up over it, but wouldn't take much out of your day to introduce yourselves and explain the signs.  Might make new friends in the process as well.  Good luck, and keep on posting.........the more the merrier around here!!  :~)