Hi Hooter,
I can't speak from experience, but I seem to remember reading years ago in RCM that someone was 'stealing' R/C planes (or at least, took over control of one of them). The memory is foggy but here goes...

The planes used to fly near the edge of a tree line. Apparently someone was hiding in the tree line and had a tx on the same freq as someone flying. When the plane got over the tree line (and downrange from the original pilot) the guy hiding in the trees switched on his tx and 'stole' the plane.

As I said, this was a story in a magazine years ago, and the details are a bit foggy. But, it does make for some amusing reading...

Bob