So when you log into your Skymiles account with the account number and password, by your reasoning, Delta shouldn't know who you are, either. And when you send Delta email from the email address associated with the account, they should assume that's fake, too.

If we were to apply a little actual logic to the situation, what would a scammer gain from trying to close an account that has no legitimate activity for more than 10 years? It's been at least that, if not more, since Mom flew Delta or used her DL linked credit card.