On a ticketed event page, there is a "clear order" option on the stage following the selection of the number of tickets the visitor wishes to purchase. It has been reported that, when this option is clicked and the user is currently logged in, the RSVP count and the value of the ticket previously selected are removed from the RSVP total within the control panel.
Say I select 2 tickets at $10 each. I decide I only want 1, so I click "clear order." When I click this option, the control panel will now reflect my RSVP as "-2" for a value of "-$20."