Inside of Referral Rock, you may see a list of individuals labeled as 'Potential Invites'.
A Potential Invite is a contact that matched one of your existing invite automation rules, but since the associated rule was disabled an invite to join your referral program was not sent. Once an invite to join your program is sent (via an Invite Email Campaign) or the contact joins the program they are a potential invite for, they are no longer listed as a Potential Invite.
You can view your potential invites on your Sources & Rules page.