Aside from insisting to remove the item from the glass yourself..............
In my club, you break it - you bought it, or you are arrested with a PI and
destruction of property. That includes speakers, broken table legs, lighting,
etc.
Managers and servers are to never get into it with customers. The reputation
of your business or even yourself as a professional should not be risked at
any point and contingency plans must be in place when it comes to security.
So to answer the question:
1. If it looks like he's really going to f&ck up your speakers, you should be
seeking enough security to efficiently contain the customer away from the
crowd (outside is good), and your soundman to assess any damages to equipment.
2. Have other security and bussers double time the rest of the drinks and
customers (Don't miss the 2:15 because you got a man or two tied up in your
situation)
3. After he is contained, warmly and calmly notify the customer of his
transgression and tell him his options. Something like, "Sir, as much as we
appreciate you coming in tonight. You may have ruined some of our
equipment........"
4. Wait for damage report and give him the choice to pay for it on the spot
and avoid a criminal case. If he is really hammered and belligerent, hand him
over to the police and press charges.
The reason you lost your cool was you had the goal in your head to smoothly
close the bar and he was keeping you from achieving it. You ran out of tools,
could not control the drunkard and so it got emotional. It may seem like
overkill since your speakers were probably just fine anyway but this incident
should point out holes in your security plans. This is more complicated of a
situation than say, some idiot punching a hole in your drywall - that's pretty
straight forward but both should be approached in the same manner. This way
you won't lose control of the situation and your bar and your ass is covered.
P.S. If you don't 86 the guy, have the staff keep him on a short leash with
the sauce.