In the 2000 election I had someone take a sign which was nailed to my arbor. However, I had a calculated that might happen and had put very generous amounts of axial grease on the back of the sign. The guy that took it, jumped into his car and speed off, as he heard me coming out.
My only satisfaction was that he got the grease all over his hands and steering wheel as he speed away. (heh, heh, heh)
Great idea! You can also buy a product called "Tangle Foot" It is a very sticky insect deterrent you put on the stalk of plants to trap the bugs. There is also a impulse sprinkler fitted with a motion detector that is used for running deer and other critters out of your yard. It's about $80.