This occurred to me using the fitting rooms in New Look at the weekend, marked womens with just curtains shielding us in the booth. Person in front of me I was almost certain looked like a man, certainly sounded like one (or transwoman they would say nowadays). The young female attendant however didn't bat an eyelid and waved them in handing a token. Being too polite (female socialisation) I did nothing but just went in myself, going to opposite side from them. I suppose I couldn't be 100% sure it wasn't a very tall butch women with poor style, or a TW without nefarious ideas. About 5 years ago I wouldn't have considered anyone would try their luck, this is what is happening.
Simple question, would you or have you been confident enough to challenge a man in changing rooms, toilets etc. either directly or to staff? Would you prefer the risk of embarrassment over allowing men to have unchallenged access?