The customer server rep. explained that the corporate stores have different machines and only those ones accept their cards. I said that everyone should have the machines. The CSR said that stores in airports, hotels and grocery stores may or may not accept the card. She also directed me to their FAQ:
Your Starbucks Card is accepted at most Starbucks locations in North America and in select countries internationally ... At this time, the Starbucks Card is not accepted at all airport, grocery, bookstore, casino, university, and hotel locations; nor at stores in Puerto Rico or Guam.
So don't ass-u-me that just because it says that it's a Starbucks that their card will work! Silly me!
I vented and although nothing was done, I feel better about letting off some steam.