It appears that this sign appears in a Washington, DC store -- versus all Starbucks stores -- but correct me if I'm wrong. The note says: "A 'refill' is when you refill a cup of brewed coffee that was purchased in the same store within a 2 hour period, if you have not left that store. If you leave the store and come back later, if you purchase your coffee at another Starbucks location and bring in your cup to be refilled, or if the two hour period has passed," you can't get a free refill. (Click on the image to read it.) || Read "Starbucks goes for zero tolerance on refills"