Multiple-signups-not-allowed message AFTER patron's time is over
Patron asks why system won't sign her up again after her assigned time is over. It generally turns out that patron's time is not really over. Time on computer screen may say "3:28" but her time on a machine is not over until it says"3:30". She can either wait two minutes or she can cancel her current signup ("4" on the menu) and then sign up again.