OpenCoin Inc or the ripple network itself would not need to retain those aged email addresses but only to use the roundtrip verification to one as sufficient proof to create and pre-fund an account.
Well if it's a gmail account, Google saves every message ever received or sent. So it would be easy to associate the gmail address with the Ripple public key.
True, and that uber nefarious NSA Carnivor program retains every IP & Cell network packet in a permanent Utah data repository too :-)
How paranoid do you wanna get about this ?