I'm not sure that sketchy is the right word. I, personally, feel like this is not a fair and honest transaction, and is in "bad faith". BB has to have an employee go gather the merchandise you ordered, and then have an employee work with you at the register to do the exchange. And, according to what you said, it was more than one employee (required a manager) at the register. This costs BB money. They are paying those employees, and then yet another employee to go put the merchandise back into inventory. BB is losing money as a result. And it creates busy, unncessary work for the employees. And you are in the return queue, which creates a longer wait for regular customers who are actually wanting to make legitimate purchases or exchanges. It's a lose-lose-lose (for BB, their customers, and employees)...and a win for you.
Buying a bunch of gift cards online, then buying other gift cards with them, and even doing it again...no loser in this scenario, from what I can tell. Seems in better spirit to me.
Again, just my opinion.