On the subject of trackers, a mate of mine has them fitted to all his vehicles and heavy plant machinery and has worked in his favour several times with things going for a "walk" from off of sites. He can track them on his smartphone and normally goes and finds them with a couple of "heavy" mates.
I saw a program about trackers and the police were in a helicopter flying above a main road in South Africa, The bleeper went off about every mile !!!
