Don’t give up on Apple’s new Concierge appointment system for the Genius Bars, even if it tells you there are no more appointments for the day at a particular store. The store dynamically tracks cancelled appointments and opens up appointments when they occur. But, the Concierge Web and in-store screens don’t tell you this specifically, only to “try again tomorrow.” In fact, appointments could open up at any time during the day. How about an option within Concierge to e-mail me when an appointment opens up, then the customer has five minutes to click on a link to reserve it? It’s no clear how many cancelled appointments occur during the day, or how many of those are filled up by drop-in customers.