@thomasfuchs Not quite, at least not yet. It depends a lot on how the new user would use the account. With 3 letter acronyms there's bound to be an unrelated NPR. If someone impersonates them - sure, but even then you have parody accounts which can be legal.
Do people believe there's something official in private playground accounts (like twitter or meta)? Their ToS usually explicitly says any account can be seized at any time if they deem it necessary.
@thomasfuchs If you're saying that Elon would just give it to someone with all the followers, same logo and description. Then sure. It will go very fast to the "find out" phase of trademark law. In the morning I thought nobody would do that, but then again it's Elon so he probably would.
If he deletes the account and lets someone register it again with 0 followers. I'm not so sure.