I've found that the higher priced the venue is, the more strict the requirements are. It's not a case of snobbery, because you can run into crabby people in any venue, but it seems the "higher ups" seem to have a more regulated lifestyle than many of us are used to. Every stage is different, and every region (location) as well. As a person in the service industry (and that's what show biz IS) we need to be ever mindful of the fact that we are actually servants. It's not demeaning in any way, in fact it's a privilege to serve others, and as soon as we forget that, we loose some connection to our clients.
Most musicians seem to think that the customers owe us something because we're "so talented", or that "we don't NEED this gig". I remind myself at each show that my clients are ALLOWING me to pursue my dream, engage in my passion, and earn a living at the same time ... all while (hopefully) bringing joy to them along the way.
We all had a pretty loud wake up call this year as we found out that we are NOT ESSENTIAL to the workforce, but we ARE essential to the well being of the soul, and the growth of the spirit. We need to be ever mindful of the role of the artist.
We put our heart and soul on the line and ask ... "Please accept this?" ... when that offer is accepted, it's a thing of beauty.

Don't let the small percentage of crabby patrons spoil your mission. Bring the music to the masses, check your ego at the door and cash the check when you're done. Music Business 101.