1. Event add-ons are specifically designed for purchases that do not include admission to the event.

2. Add-ons can be things that are purchased after a ticket level purchase has been selected or independent of ticket levels by selecting Require Level Purchase for Add-on Selection to YES.

3. Add-ons are generally things like traditional paper raffles, t-shirts, advertising, and sponsorships that do not include tickets.

4. You can also create event levels with zero attendees if desired. 

5. Add-ons and event levels with zero attendees will not appear on the Event Attendance grid, only the Events and Gifts grid will include the transactions.