[rjmunro]

I think it's more about the opposite. If you are the new owner, you don't want the old owner to continue to have access to features connected to your new domain.

So as a new owner you would want to remove the tokens.

[ta1243]

Intriguing, hadn't considered that way round!. spf especially is something you'd have to update

Presumably services pay attention to the TTL, so services don't have to constantly refresh.