Bill, there is a case on record of a lawsuit brought by an unsuccessful burglar who fell from the roof of the building to the floor inside when the skylight he was breaking through gave way. This was in California, of course.

Another observation, getting back to the original post. You can buy counterfeit stickers which state that the premises are protected by one or another well-known security firm. They only cost a few dollars and probably have the same deterrent effect of a genuine sticker issued by a co. which charges $50 or more per month for a real alarm system.