It doesn't matter if we can tell the difference since all men are now welcome in all women's places.
Scottish Women's Aid, for instance, tells us they have had no problems at all in 15 years of trans inclusion.
Possibly because, until recent years, no-one knew they were trans inclusive (apart from ScotGov, who make it a condition of funding) and there have been very few transwomen.
Now, tho, someone like this man might turn up, on his best behaviour & claiming to need help.
Should they let him in? And how much of a refuge will it seem to the women then, even if he is not aggressive, or if he is?
Should they refuse him for looking too much like a man? And maybe they'll suddenly have a male aggression problem.
Claiming that men can be women is complete madness.