MOst stores do have a price guarantee policy in place - if the price drops in X number of days, you can get an adjustment. It just depends on what the current BB one is, and if it's excluded from that based on the, "not valid on prior sales" (and i have no clue what it currently is, i haven't shopped and needed to know for awhile).
They have this because they know that it will irk people and they will return it - better to adjust and save the sale, than to not get it at all.