The $500 fee they collect from the person booking the event and very likely they won’t touch your equipment but they will hit the Circuit breaker. But like I said this is between the hall & client booking the events. Hopefully the client passes this on to you before you sign the contract with them. As the venue is booked first they likely know about the rules, but may think it’s no big deals. I’ve had to deal was some crazy crap went being forced to use crappy house systems. One time I had to go and get my system out the van went the house system failed. Likely I saved the event by having equipment ready. Had I not been there would the other DJ had his system ready? Same thing with this one, we know the music isn’t going to be loud enough. Then I offer the solution which they may have turned down before during planning. But it will cost plenty but will save the event. Maybe it’s all my time as working corporate event & college events, I have no program breaking its down on how things are going go. Usually the only ones who are really a PIA are other DJs or think they are a DJs.