I don't consider Brits as a "sub-class of Americans;" I consider native English speakers (from the US, the UK, or elsewhere) to be capable of negotiating the differences between the written versions of US and UK English without too much trouble. Some of us who predate the Web or Internet (which are usually, and incorrectly, considered to be identical) have, say, seen US books and magazines in UK bookstores (I did, roughly 30 years ago), and I know that US movies and TV shows are fairly common in the UK.