This did not happen to me, but it did happen to a close friend who plays guitar in a local band....
They were playing a show at a bar a couple towns over and as the night went on, a woman kept coming up to the stage and trying to join the show. Totally lit from what he tells me. During the last set, she storms the stage, grabs his mic stand, and starts singing into the mic....briefly...before she passes out, taking out his mic stand and spilling her drink all over his pedal board. He was not happy.
But then he had to laugh when he found out she was the drug and alcohol counselor at the local high school.
Ironic.