I drink Starbucks daily. I would love to see this. I can't imagine using Bitcoin in a scenario like this. If this happens and other retail outlets are forced to compete Bitcoin will be accept around the world almost instantly. Very exciting. I hope it happen soon.
Thou, bitcoin is known around the world, all I can say is that we should still preserve this kind of stuff. Not everything can be handled by bitcoin. It is good to innovate but come to think of it, old habits die hard... I think that it will be a big change for the customers..
We have seen a breakthrough from Burgerking last year and got a strong controversy from Parliament, some of them even described Bitcoin as just monopoly game money trying to be valuable, while not having any value at all.
I think Starbucks will experience similar obstacles and this will be a cycle of legality that has never been achieved at least in the next 2 years.