Last paragraph of the article you linked:
“Starbucks released a statement saying “We apologize for the misunderstanding at our Bartlesville store. Our store partners (employees) In no way meant to dishonor or disrespect members of the military or their families. We are sorry for the loss of Sgt. Christopher Gailey and send our condolences to his family. To express our gratitude to those in the Bartlesville community who serve and have served in our armed forces, we welcome any of our troops or veterans to our Bartlesville store to enjoy a cup of coffee on us.”
I personally would I just asked them to put the signs away or something, especially if there were kids around. Otherwise, as mentioned upthread, I would have offered them a coffee.
Then again, there are other reasons to avoid Starbucks other than their lousy, overpriced coffee: http://www.freerepublic.com/focus/f-news/2807012/posts