Just wanted to throw out a question ...

Let's say you're an American-based publisher that is editing a short story anthology collection in which one or more of your authors are British. Do you leave in the differently spelled words (favourite, colour, etc) or do you consider them to be incorrect? Discuss.

MY vote is that you leave in the words ... it's a story written by a British author, in HIS words ... The story might or might be about British people and/or British places, which makes the case even stronger.