So sorry to hear about the loss Beth. I was at the show, and can't believe that anyone would have the nerve to steal something so precious. I agree that some sort of security measures need to be implemented, as there are some very valuable species at these shows. Ideally, we could hold shows such as the TARAS one, and trust that no one will pull anything like those two "punks", but sadly, society is hardly ideal. The sticker method that was mentioned above, sounds like the best idea to me. It doesn't require a lot of hassle on the part of the vendor, or the buyer. Perhaps a few more people at the door would be necessary, but this is hardly a nuisance when you look at what was, and has been lost in the past.
I hope the tortoises are found, and that those who stole them are punished appropriately. Best wishes Beth.
"Trace the moment...Fall forever"