Like I said in another post:

Seems like a good time to remind everyone just a few months ago he took two active usernames from their users without warning. Both @x and @music were in use and taken by Musk with no warning and no recompense.

At this rate I see it as completely possible that someone buys one, and the first time they don’t update within whatever Musk feels like is “too long” that day, he takes it back with no warning.