So I've got iOS6, and I've got Passbook ... and supposedly Starbucks is passbook-enabled. Their app prompted me to acknowledge it's settings, and I've specified my favorite Starbucks stores. But I have no idea what's supposed to happen next. Whenever I got to Starbucks, I'm still launching their app as I always have, and I'm never prompted to launch Passbook, or anything else. How is this supposed to work? Do I need to enable constant GPS in order for it to be of any use? And aside from that, what benefit is there to having their app (or any other company's for that matter) setup with Passbook? Maybe I'd understand better if it did whatever it's supposed to be doing, but so far I'm totally confused.