Americans also call US customary units "imperial units", even though they're not the same as the British ones.

Imperial pints are bigger than customary pints, for example.

In my country, NZ, we refer to beer as pints, and order them as such, but a pint isn't a legal unit of measurement, so it's accepted that your pint will vary. The good establishments have a chart on the wall explaining how many millilitres map to their "pint". And a pint of high alcohol beer will often be less than a pint of average alcohol beer. 473mL vs 568mL typically.

It's not illegal to serve someone a "pint" if they ask for one, but it is illegal to offer a "pint" for sale.

So at the same establishment you could order two pints of beer and the high ABV one would be smaller in volume? That would really bother me or anyone calculating the unit cost of ethanol.

They make it clear what size they serve it in on their beer menu, so it's not too bad.

...the sad fact of which rears its head in American drinking establishments nationwide.