yes, they can come back - under a new account. my point was that based on the grayed out "guest" status of Purported Online Luminary*, it appears that this account has been ended/terminated/suspended/etc... aka banned. i could be wrong. one can also voluntarily delete their account.
* Purported Online Luminary, formerly known as Jump Up Like It's A Nightmare! screen name doesn't have to match login/account name, but your posts revert to the latter when the account is shut down.