Hahaha... I ve done the same thing and seem doesnt work. The problems is there were too many of them. You cannot just put a note like that coz u might put your house in danger, you now what i m saying?
In my case, after have enuf with those stupid inconsiderate driver, what i did was putting some 2" nail spike on the ground at strategic location. Dont put too many nail aa.. otherwise it will turn too obvious. And you must do this at middle of the night and at all roadside infront of your neighbouring housing!
Seem work for me! hahahaha..... Never mess with my territorry!!