Existing event registrants are not warned in BBIS that they are already registered for an event. The warning is only shown once they are in the batch so the user is unaware their registration failed. If the registrant A buys tickets for guest B as a gift or without informing them, B has no way of knowing they already have a ticket/registration.
We're currently evaluating this issue for a fix in a future release.
Steps to Duplicate
Prerequisites:- create a new event with a registrant (A) with a guest (B) to the event.
Test 1 a guest tries to add a new guest
Constituent B logs in and adds a new attendee there is no error or warning in BBIS
Download the transactions in BBCRM
This will generate the error as Constituent B is already down on the event as a guest
Test 2 a guest tries to register and add a new guest
Constituent B logs in and tries to purchase 2 tickets
Attendee 1 is Constituent B and he’s adding a new guest
3. No error is seen in BBIS. In this case you can see the 2 registrations
This then flags the existing registrant in the batch again and prevents them being added twice