I'm not alone up there. I have a co-pilot, and the host or hostess for the trip. We watch them. It's like babysitting sometimes, but we have to watch. I can lock the cockpit if we have a drunk on board, but most people on charter are pretty cool, at least on the outbound.
If push comes to shove, I can throw a healthy punch, and I have handcuffs if we really need them, but I've never used them.