According to his statement, law enforcement personnel are exempt from the "request":
"Our company’s longstanding approach to “open carry” has been to follow local laws: we permit it in states where allowed and we prohibit it in states where these laws don’t exist. We have chosen this approach because we believe our store partners should not be put in the uncomfortable position of requiring customers to disarm or leave our stores. We believe that gun policy should be addressed by government and law enforcement—not by Starbucks and our store partners.
"Recently, however, we’ve seen the “open carry” debate become increasingly uncivil and, in some cases, even threatening. Pro-gun activists have used our stores as a political stage for media events misleadingly called “Starbucks Appreciation Days” that disingenuously portray Starbucks as a champion of “open carry.” To be clear: we do not want these events in our stores. Some anti-gun activists have also played a role in ratcheting up the rhetoric and friction, including soliciting and confronting our customers and partners.
"For these reasons, today we are respectfully requesting that customers no longer bring firearms into our stores or outdoor seating areas—even in states where “open carry” is permitted—unless they are authorized law enforcement personnel.
What authority is granted to law enforcement personnel that is superior to the Constitution's Bill Of Rights for citizens?
So the guns aren’t the problem. The customers are the problem.