I found the posts below on the Austin Seven Friends Forum and wonder if military vehicles are being targeted in the same way?
Tracking devices.
For all the people who like to enter cars shows, it would seem that cars at shows and events have become targets for criminals. A tracking device is fitted to the car at the show then is later tracked to the owners home address and the car stolen. It is probably worth giving your car a good look over before you leave the show just to be on the safe side.
Re: Tracking devices.
I saw these images posted on a classic Ford page I follow, these were found on a car after Ford Fair at Silverstone, there has also been reports of cars going missing after this event also
Photos by joda_2k