Had that exact thing happen about two months ago. Long drive to a gig north of Seattle and when we got there we couldn't set up because they had a table with people eating dinner at it exactly where we needed to set up our Keyboards. My bass amp went up against the ATM machine on the other side of the "stage area" and we had to wait for those folks to leave before we could get set up.Host: we need to wait until the people at that table leave, and then we'll move it, and that's the stage.
Me: Who booked this? WHO BOOKED THIS???? HEEEYYYYY!!!! AAAUUUGGGGGHHHHH!!!! WHO BOOKED THIS?????
Host: Is there a problem?
I was not a happy camper because it was a 1½-hour drive from my house and the BL wanted us there 2 hours ahead of time. So we all got there; moved all our gear into one big pile - OK it wasn't really a pile but it was all crammed together - and then we had to wait an hour for those folks to leave before we could start our set-up.
I was not pleased, right up until the end of the evening when we got paid. Then everything was fine.
Amazing how $$ smooths over everything. Next time we played we asked them to be sure that table was moved at least 2 hours before start and they did that. They are actually quite nice folks and more than willing to be accommodating. We have three more gigs set up with them throughout the first half of the year. One really nice thing about this is that I didn't have any trouble getting "up" on that stage.