Used to be that the Captain would put on his uniform jacket and hat and walk back to the cabin in all of his august majesty. He would then scare the bejezzus out of the pax and secure a promise of compliance. (If the Captain thought he might get punched, he would send the second officer who was expendable.) Since 9/11 that doesn't happen and if the flight attendant asserts a safety issue and states she is concerned and maybe a little scared, the Captain really has no choice except to land at the nearest suitable airport. With these kinds of events, the crew is pretty risk-averse. Flight Attendants put up with a lot of chicken-$h!t stuff so one someone goes over the top on em, they are likely to strike back with a diversion.

I once knew a USAir Captain whose claim to fame was a pax going berserk on a flight from PIT to LAX - took her clothes off and was making a mess in the back lav. He elected to overfly Denver and continue to the destination. I bet he didn't drink anything the flight attendants brought him after that.