My, my, you mean, it's not one of those disdained Memphis ghetto resident thugs!!?? Seriously, when ole Shirley and I went to Neyland or any crowded venue, we wore a leather or canvas fanny pack. All valuables were in it. But with the zipper side facing our front. And, a latch hooked short chain to both side rings. That way, you couldn't snatch and run or vanish into a teeming crowd, cause the pouch would still be secured to your pants. I've felt questionable bumps to my back side but never had the pouch belt undone. Nothing is 100% foolproof, but such precautions greatly reduce theft. Beyond that, as someone suggested, activate alert notices so you get email and text notifications of your card being used. You can stop further transaction efforts right away.
For the person who asked how a thief can lift a card without being seen with so many cameras about, here's a fact. Distraction and slight of hand. You'd be surprised how a trained thief can steal something right in front of you and you not even notice. Yes, there really are training sessions for such people and has been for centuries. Cameras make it harder, but it's still doable. I think in my college years, I saw a video about this. Memory is dim now, but I think it had to do with a rash of thefts on campus.