Unique Email
Requiring unique emails stops the same email address from signing up more than once, so each person can only respond a single time.
Also called: require unique emails, one signup per person, prevent duplicates
This guards against duplicate or repeat signups on forms where one entry per person is the rule, like a vote or a one-per-family RSVP. It works alongside warnings for people who try to sign up again.
Want to set this up? Require unique emails