Overview
If you have customers who are signing up multiple times and creating duplicate submissions, you can enable a feature to prevent this with the Prevent Duplicate Signups setting.
Setup
Go to Settings > Site Details and select the Prevent Duplicate Signups checkbox.

How it works
When this setting is on, we will look to see if any people on your list are using the same email. If the person with the same email address is not part of the current family, and they have a family member who is actively on the list, the signup will be blocked as a duplicate.

