Oh, i didn't know you could turn off unique email requirement. That will be very helpful i think. Are there any negative ramifications of turning that off that you can think of in regards to the rest of the system?
Would have to disagree with the emails if you allow this, you will get the same customers register over and over again and have multiple accounts rather than reset password. You will have to constantly monitor and merge customers. A better option would be to have a warning for the customer to say this email address already exists do you still want to create a new account under a new name/company or retrieve the password for the existing one.