Generally AC they don't (catch cyber criminals - only the dumb ones)
These sort of people don't set up an account with their frindly local ISP who logs their details, they'll send mail via open relays, compromise other machines and proxy through chains of other computers.
I'm rather assuming that Harry isn't a budding cyber criminal but is either intent on a practical joke or wanting to send a romantic mail or something of that sort and is confused between anonymous and encrypted.