bekitzur- Where did you hear that? There are more than 65 starbucks items currently on the OU website.
PBA- Maaris Ayin is not to be confused with having to be dan lkaf zchus. Even if you can think of 10 valid reasons for someone being in a treif restaurant, it doesnt mean others will think the same.
Also, did you know that something that is assur to do because of maaris ayin may be asur even in your own room with noone else around to see?
See below for an in depth article by R’ M.D. Lebovitz of the Chof K on maaris ayin. http://www.shemayisrael.com/parsha/halacha/volume_5_issue_12.pdf