Interesting one for us last night. A do in a big club room about an hour's drive away.
PA was provided - they asked for, and we sent, a full spec. I brought my little cab 'cos I knew the hump was going to be a pain, and the PA would take care of FOH.
We got to the venue to find the most tin-pot PA in place.
PA guy (pointing at the stage box): 'There's your ins for the desk'.
Us: 'Err....'
PA guy: 'You do have XLRs with you, don't you?'
Us: 'No. You're doing the PA. Not us.'
Eventually we cobble something together, during which it becomes apparent there are no channels / mics available to put the drums or bass through the PA. Ah, well.
At some point, I ask when the monitors are arriving.
PA guy: 'No monitors. Sorry.'
So, the theme of the day was to keep the volume down.. basically 'cos we had no choice. And it actually worked out OK in the end.
Incidentally, situations like this are one of the reasons I don't fancy going down the IEM route. At least I had something with me.