If you scan a QR code or search for an attendee and see that they're already marked as checked in, check a few things:
Ask the attendee — They may have already been checked in by another staff member or at a different entrance.
Check the attendee list — Look for duplicate registrations or similar names.
Verify manually — If you're certain this is an error and the person hasn't entered yet, you can note it and proceed. The status display will show "Already checked in."