Unique Address

When setting an "address" component within a Webform to "unique", a user can still submit the form again with the same address.

Use Case: a user can submit the webform to redeem a prize. While we could limit by email, users could enter multiple emails and continue to redeem, whereas it is more unlikely that someone has multiple mailing addresses to enter and receive the prize in the mail.

To replicate: Install the Webform module. Create a webform. Add an address field as "required" and "unique". Fill out the form once with a specific address. Fill out the form again with the same address. A submission still goes through with no warning or error message, even though the addresses are the same.