My experience of singers pulling the video lead out

[ddouglass]

When they are that drunk I refuse to let them sing or be anywhere around my equipment. I also inform the bartender so they can cut them off. If they don't want to do that (some are reluctant to cut-off a paying customer), then remind them that they can be held responsible if that drunk leaves and gets into an accident.
I also use long enough cables to route them away from the traffic area.