This anecdote is rather appropriate in today's climate:
During World War One, the Liverpool Echo reported (perhaps fancifully) that a student travelling to London in a women-only compartment had sat alongside two nuns. On the way, the young woman noticed that one of the sisters "disclosed a masculine wrist". The student informed the guard and when they reached their destination, the nuns "found themselves under arrest as dangerous German spies".
Thanks, DdraigGoch That made me laugh out loud! I wonder if it is true?