Question about Amateur Nights in General

It's usually strippers from other clubs auditioning. And they always wear stripper outfits

They will start off wearing stripper outfits and not regular.

I did have one dancer once go back on stage in basically regular clothing (she was getting ready to leave on a really slow afternoon) and flash me her tits for a couple of bucks. It was pretty damn cool.
I was known by the bartender at the place and it was shift change so no other night dancers had started yet. I think the bartender told the dancer who was leaving to say hi to me before she left. I never saw that dancer again which was too bad because she was really hot.

I haven’t seen an amateur night at a club in years, if not decades, but the general thing to know is they are usually not amateurs. They are strippers from other clubs trying to win the amateur night prize money.