Played a festival couple of years back, I emailed the tech guys to ask about the house rig and whether I'd need to take mine and was told "we're getting an 800 watt Markbass head and a 4x10 cab, hope that's ok..."
Yeah, I guess I can slum it with that
EDIT: just realised the thread is about backline at permanent venues. Ah well. Can't be bothered to delete this