Although I'm late to respond, I certainly hope you passed on this, glocke!
I've been in host bands for jam sessions a number of times and, even when present, people just don't know how to respect other people's gear!
I go to the bathroom and, suddenly, I hear my rig breaking up like crazy. I run to the stage and tell the idiot to either turn down, or get off the stage! Hell, the room wasn't even that big, and my rig ruled when we played there as a regular gig.
Sheesh.......
Never again.