Around where I live, alarm signs are the norm. Although one thing I discovered when I used to sell alarms around here, half the people with alarm signs don't actually have alarm service. Either they just left the sign in the yard from the previous owners, or stopped their service for one reason or another.
Personally, I avoid signs and stickers in general, but do feel that advertising you have guns is not the best idea. Plus, I have no guns...they were all lost in a boating accident