Yeah, kinda like I was saying.
Look, ASCAP/BMI is NOT going to go after a musician or band. That would be against their

stated guidelines! Their own guidelines call for charging the license to venues and organizers. They can't hardly then go after those they said in THEIR guidelines ARE NOT RESPONSIBLE.
Let's apply a little common sense here guys. ASCAP is the law here. No one else is going to even think about this issue. You think the cops are going to investigate this? The FBI maybe??

If ASCAP says you're good, you're good.
Okay, yes there may be a violation of copyright law here... by the organizers, not OP. ASCAP are the ones enforcing that, and they say musicians are okay! Sheesh people.
Okay, ASCAP sued the Girl Scouts... the organization! They did NOT sue the girls who were singing!!
See the difference?
I would sign this in a heartbeat and do the gig with no worries. No need to cross your fingers, YOU'RE NOT DOING ANYTHING WRONG!