I mean... if you are mature enough to show up and pay dues, what's the big frikkin' deal????
The "big frikkin' deal" is if you didn't already have a list of rules conspicuously posted -- then it becomes awkward. I agree it's common sense not to train in makeup -- or with anything other than very short nails, or while wearing jewelry of any kind, or in an unwashed gi. But I've said it before and I'll say it again, people in the US are going to think of a dojo as being like a gym, and people do all those things at a gym. If you've ever been in a gym and seen the way some women get all chicked out to work out, you should know that there's a cultural thing. Working with it seems like the sensible thing.