In Splash, an email is a guest's unique identifier and is a requirement when adding or importing to your Guest List as well as when creating your registration form.

If a contact's email address is missing from your spreadsheet or inputted incorrectly, then that contact will be skipped over entirely.

After your import is complete, you’ll receive a confirmation email, which will notify you of the number of contacts that were skipped over.

If you need to import or add guests for whom you do not have emails, the workaround is to use a unique, dummy email, per contact.