Haven't happened to me, but....
YT is Google's and Google tried that silly real names thing when they launched G+. So after a couple of months of "nymwars" they allowed pseudonyms providing that the pseudonym has some kind of history and credibility (blog, other established accounts on various sites, etc...).
New you reminded me of something about Google trying to establish some sort of service that will register pseudonyms but I just glanced over that article so I need to check that again.