I'm not sure about EU, but as of an hour or so ago they placed a check for every US account to see if it has had a character recently moved to it before they will change a name.
They even go as far as to offer you a brand new account with all of the expansions as compensation.
Easy way to get ALL MOUNTS!! Major EXPLOIT - Forums - World of Warcraft
Here's a thread addressing it.
Just letting people know.