Hi, I think a useful feature to have for concert-type events is the ability to display the number of check-ins that have been processed at the event.
This figure could be placed on the event page associated with the number of registrations so that the event team onsite can view it in real-time as check-ins happen.
This is helpful for situations where check-ins are lower than registrations, so the organiser will know in real-time how many seats are available.
This will help to process walking or late onsite RSVP's, because the organiser will have an idea of how many seats may be available to re-assign.