Much like posting something on imgur or another site, there's not much they can do after that if people copy and share it elsewhere. I'd say the same standard applies to something a player has made in game where others can manipulate or otherwise take some measure of control of it. The big difference is that this is a closed system, so some system could be devised to root out such things.*
Another issue is the concept of account deletion. I don't think it's been done in the past at all. It might need to be addressed in some manner.
*additionally: The thought occurs to me if such "personal data" would be their image on something like a shield, knarr sail, etc where they might intentionally sell it or trade it off, but may unintentionally get it stolen or otherwise removed from their "possession" involuntarily. Would deletion of such items be fair in the game? Might it be better that a warning is given that personal data shared into the game space may not be recoverable or deleteable?