I am well aware of that, but I'm comfortable requiring that new customers don't register an account with an email address foolishly designed to resemble another customer's email address in this particular way. We don't throw away their specified mailbox address, we just don't accept registrations which look suspiciously similar, or intended to cause confusion.
I repeat, this has absolutely nothing to do with the mailbox address, where we send mail.
I repeat, this has absolutely nothing to do with the mailbox address, where we send mail.