I have been queried walking into the ladies (only once
)
And i would absolutely confirm to a man in the loo that it was a ladies, if in a public place i would also complain if i could to someone else
However, if it was a trans woman...I probably wouldn't
And in the same situation i would probably be doing that dreadful passive aggressive muttering ...although to be fair i would probably be thinking "is this an American thing
'