I had an Ask Alex reader query a couple of years ago regarding passengers who had booked and paid extra for emergency exit row seats (window location) between Brazil and London with TAM.
The passengers were UK nationals. They were denied use of these seats because TAM insisted they had to be Portuguese speakers.
But when they had made the booking online, there had been no advisory to that effect (on the website).
TAM did refund the surcharges and promised to amend the wording on its website.