A no-hat rule is silly IMO. I wear a hat 99% of the time, a baseball hat with either a hockey, snowboard, or motorcycle reference, my other passions. Our guitar player wears a nicer hat and always gets compliments on it. Our drummer usually has a hat on. When it's crazy stupid hot here in Missouri, we have been known to wear shorts to gigs as well (but no, not cargo shorts). No one cared. The tip jar still got filled up and people dug our set.
If you're playing in a pit orchestra or a wedding gig or a corporate event, sure, I get it, you dress up and do not wear a hat. But for the rest of us playing bars and clubs and outdoor gigs - please.
If you're playing in a pit orchestra or a wedding gig or a corporate event, sure, I get it, you dress up and do not wear a hat. But for the rest of us playing bars and clubs and outdoor gigs - please.

"'