What exactly is a "Boston strip steak"??
Being from Boston, I have no idea. Then again, the term "New York Strip Steak" was not used in NYC, nor "Kansas Strip Steak" in cases. A strip steak is supposed to come from the top loin, and if so is a better than average cut of steak, one that people debate versus the various rib steaks as a premium cut of boneless steak.
Next time you see it, ask the waiter to get an explanation why the restaurant uses the term. That should be fun...