According to
http://www.wowwiki.com/Patch_3.3.5/API_changes it seems that addons can use the new API functions of 3.3.5 to get that information (including surname for example) and so could send them through hidden channels or something like that.
And it seems that you are your own RealID-friend so addons could let WoW send a message to yourself and then get the information. And I haven't read so far that these functions are callable by Blizzard code only.