My mother, brother, and I got thrown out of Westminster Abbey because my brother didn't remove his hat (we're Quakers. Hat-honor does not apply), so I thought hat-removal was standard in the UK, too. We were a bit young at the time to be checking out pub etiquette, though.

Hat-removal is standard here. Whatever you think of it, it's a very practical tradition in Texas where hats tend to be very large and are often a nuisance to the people sitting behind you. We take hats pretty seriously. I'm not aware that Stetsons are a tradition in Europe, though, so I can't imagine it's as big a problem there as it is here.