@nolan This is part of why I haven’t flat-out deleted my Twitter or Facebook accounts yet: to make sure nobody grabs the name.
That and every once in a while I still stumble on something where I’d previously used a third-party sign-in. I reactivated a newspaper account recently and it wouldn’t let me generate a new password because it associated my email with my FB login. I had to sign in with FB in order to disconnect it from FB!