Hi Rip,
I found a few links on stolen bonsai and security and put those in the
bonsaiTALK Links folder under Misc->Security
Recently, one of the gardens was putting in some kind of security system with the new display. I didn't get many details, but I think they epoxied magnets to the bottom of the pots and mounted reed switches in the display benches. Reed switches are inexpensive magnetically actuated switches. Just two strips of iron in a glass envelope. When a magnet (glued to the bottom of the pot) comes near, the contacts close and stay closed as long as the pot is in place.
This way, if a pot gets pulled from a bench, (or a wire gets cut) the circuit will open up and an alarm can be actuated.
I think this system is very practical and fairly inexpensive. It probably works best if no one knows that it's even there.
Regards,
Matt