So how is your plainclothes security, cameras and force attuned employees going to tell that someone isn't just holding their phone up like they are buying an item in-app when they're not?
Seems that they're going to have to have some sort of system to verify the purchase... plus you're going to need a fancy Apple bag before you go waltzing off with your stuff... so I'm sure they have it sorted out. Maybe someone at the door to check your receipt or create one, so you can't walk in and out 5 times with the same item? It's just cool you can more or less do it on your own and I love that you can order on-line and then go pick up at the store. I've wanted that for years.