“From the Noda B’Yehuda it seems that there doesn’t need to be a pressing need to be mattir on the road, just the fact that you don’t have an alternative makes it an automatic b’dieved situation.”
So according to this, I would assume that the reason why travelling was the only thing mentioned on the Star-K website is as I stated above. If you are not travelling, how would you have a situation where Starbucks is THE ONLY option? If you are at home, you have your own kitchen, but if you are travelling, you do not.