I have known people who would pull such a scam: Buy a new (component), open it, install it, return the old one in the new box. That was usually a key indicator that I needed to disassociate myself from those people. Personally, I see it as stealing. I've never pulled this scam myself.
But, point is I always wondered what happened. It seemed to me they would be sold open-box at their discount. I felt sorry for the poor sons of guns who had to follow these guys unkowingly. Sorry it took so long to get restitution.
Yes I would call it stealing and its also called fraud.