Have you tried testing this yourself by creating a new account, then another with the same email address? Sometimes people put special characters in a field when they are typing, such as a space, that may not be visible when you simply compare the two email fields.
If I had to guess, they probably didn't get their registration email from the first registration because the email address has a space or special/hidden character in it, so they registered again, getting it right the 2nd time.
Doug
Moderator: Community Management
Captain Kirk: "Once again we've saved civilization as we know it."
Dr. McCoy: "And the good news is they're not going to prosecute."
