Dirk is right. You are representing the venue if they hire you so why would you crap something irrelevant out? I've known bands to flip out on the venue due to stuff like this. Don't waste everyone's time if you think the band sucks. And if you take the job for money and still think the band sucks you still better do the job right or you suck.
Kings Of Leon's folks check GP out. They contacted us to do work but we were smack dab in the middle of that first Modest Mouse leg and had to turn them down. Beulah called me direct after spending 6 hours straight on here looking for someone to do posters for them. Wilco came to us through here because of a Spoon poster we did. We just got a call from a HUGE band because of GP. A band we'd never ever think would contact us. You're kidding yourself if you think people aren't looking. Foolish to talk shit on anything but Richie, Murphy and Dave here.
And Kings of Leon are one of the more interesting new bands out there. At first pass their lyrics and singing style makes no sense at all. Far from straight forward standard rock in that sense.
Some of you are gonna hafta learn a lot of hard lessons...