Well, I live in Austin, which isn't a very good town to tour though of you're a metal band (unless you're huge), and Plea kept booking dates here for a couple of years but no one was showing up. After Depravity came out they had a stop through here and maybe 10 kids showed up to see them so the venue had to tell them they couldn't give them as much as they wanted. They threw a fit about it and refused to leave the venue and kept throwing around "we're signed to facedown records, no one on our label will ever come back here" and just making fools of themselves. So the venue threw a little bit more money at them just to get them to leave. That venue pretty much refuses to book Christian bands now (except for ABR because the owner likes them so much).
The next time they came through San Antonio, and it was pretty much the same story. No one showed. The venue couldn't pay them. So they posted the promoters phone number and told kids to call this guy all night until he gave them what they wanted. He eventually had to make peace with them but he still had to change his number.
Plus a number of personal encounters I've had with them since they've gotten bigger where they completely blew me off, after me and my friends followed them to every tour stop we could make, fed them, and were litterally the only 4 people who showed up when they toured with Inked In Blood.
I understand they needed money and touring was how they made their living, but if kids don't show up to your shows you have to know that you venues can't afford to pay you exactly what you're looking for.
As a promoter I can tell you that part of the game is taking a risk on kids showing up to see shows. When you offer the band a guarantee, and kids don't show up its still on you, the promoter, to pay the band. It's completely legitimate for the band to want to get paid. The promoters for the venues in your town are the ones that sound like d bags to me. If you offer a guarantee and no kids show up, you cut your losses, pay the band, and make up your money on a different show. You don't just stiff the band cause you made a bad judgement. I've personally booked these guys a number of times and I've never had anything but nice things to say about them. But hey, to each his own I guess.