I had a guy who was standing very close to my guns once and checking them out. Could of been a innocent guy checking them out and he didn't exactly seem like he was gonna do a grab and run. Later i found out he wanted to know if my heavy barrel Savage was accurate so I let him shoot it.
other than that I had a few people comment on my S&W 357 and 44 and I asked if they wanted to shoot them. Other than that never had a issue with anyone grabbing and trying to run of with my guns. Thats a very good way to get shot or get a beatin.