I had no idea that there was a British difference for High Tea to the American one :S And I live in Britain. I guess the only time I've heard it used though is when my American aunt took he to High Tea at a posh hotel on her birthday. Never knowningly had to distinguish between tea in the afternoon and tea at the table.

I did spend a lot of time recently looking into the accidental expropriation of words from ancestors that result in redundant usages. The most famous in England is probably River Avon, where Avon is a Celtic word for a type of river. Same for Rivers Humber in Canada. Lake Laguna, Table Mesa. Orkney Islands, where the -ey is an ancient suffix that meant 'island'.