People do try it on.
Many years ago Mrs Bas and I were on LoCo to Canaries and had paid for extra legroom at exit which was on Stbd side opposite boarding door.
People enter, eyeball our seats and start to complain about 'bad legs', 'stiff joints' etc. - can we sit there?
CC, who'd seen it all before, sent them on their way.
Oh, BTW, those clowns weren't 'foreign'; they were full on white Brits.
My view: who cares about the colour of your skin; if you are trying it on then on yer bike, mate!