This is an interesting post, and I am looking into it. However, one thing off the bat, I can't just create any email account and then email from it. You have to email FROM THE EMAIL USED TO OPEN THE ACCOUNT. So, as long as you were the original user to open the account, you should
A) Know what email was used.
B) Be the only one to have access to it.
How do you verify that an email that seems to be sent from
john.doe@example.com actually IS sent from this address? It is not very hard to fake the originating address in an email...
http://en.wikipedia.org/wiki/Email_spoofing - and just a quick google search for "email fake sender" already gives me several web servic es in which I can enter any mail I want that seems to be sent from any other mail address.
If you send a request for confirmation back (again, taking care that you don't just hit "reply" - this might send the reply to a different address!) - which you don't(!) - then at least the mail account needs to be pwned too (probably not too hard, but at least a bit harder than just faking a mail).