Heard a story a while back about a series of thefts in the US.
The thieves targeted aircraft that had just had an upgrade with brand new radios/GPS's etc.
The brand new gear would get stolen, and was promptly replaced by the insurance company. The gear would be listed as stolen, serial numbers being distributed to all avionics shops so that they could look out for the "hot" gear when someone brought it in for an install or a repair.
Very soon after the replacement radios had been installed the thieves would come back and swap the stuff they had stolen earlier for the replacement set of avionics. The "hot" gear was back where it started.
Hey Presto the thieves now had Avionics that no one was looking for that they could sell without the same risk of being caught.