No -- that's a terrible idea since most people (newbies I guess) would change their names constantly because they don't like their names currently. Also, people may be able to get past filters in place to block curse words and the likes.
It's in my opinion that when you sign up for the site, you better choose a screen name you like. If you don't like it, then there's two options: a) making a new account or b) maybe before hitting enter, recheck to see if you really like the darn name.
