That was the one concession the EU made because people were used to buying milk and beer in pints rather than litres.A half litre of either is less than a pint. When I go to the deli and ask for 4 oz of something, only to be told that, "We don't do ounces, only grams", I take great delight in replying, "OK, then, give me 114.5 gm of..."
milk and beer are sold in metric but we have been allowed to have a special measure of 568ml and still call it a pint. We can have 1/2 & 1/3 pints as well 284 & 189ml
I don't frequent any bars/pubs but when I was MUCH younger and pubs/bars were a million times more welcoming, yes, many gave their regulars free drinks. There is one local bar here that gives ALL customers a miniature of something rather nice, for a chrrissie pressie