Donna D's photo of a sticker regarding a motion detector gave me an idea. Perhaps a good deterrent would be to have a motion sensor or accelerometer turn on a loud siren/horn. A person could have a hidden switch somewhere to arm/disarm the system. The entire thing should have its own backup
battery so the system would work if the thieves cut the tongue
battery. Better yet, detect that the tongue
battery has been disconnected and have the siren go off in case the thieves were just after the battery.