Ever bought a coffee in 7/11 or any rest area etc ?
I personally don't drink coffee, but I personally would not drink from starbucks nor any non kosher store who prepares there coffee together with the rest of treif store, they use the same hands filled with the kentucky fried chicken or in starbucks when the just finished cutting in half the cheese burger which they warmed up in the microwave/oven/toaster and then go fill your cups of coffee up and use the rag to clean the machines with there oily hands touching everything, and they use the same dishwasher for the basic metal utensils which they use to make the coffee, and together cleaning all the plates which served the food and non kosher cake /meat /cheeses...
To me I see it all treif, and don't see why there's a heter to drink from these stores, the funny part is I have never seen any rav nor and hashgacha given or allowed such coffees from such stores..
Or maybe there is and I never saw it, I mean a normal hashgacha not some rabbi out in the boon docks.
Unlike glass which is totally different which im sure lots hold its ok to use whether a bar or on a date...