I don't see how this new policy will stop the abusers. You can still return the phone/tablet for a replacement.
Now if I am hell bent on abusing the system, and have no need for the device, I will just keep returning the replacements as well citing different reasons. After a couple of returns, I am pretty sure that they themselves will give an option of refund against replacement. Hence, all this policy change is gonna do is create issues for genuine users.
Like I have already pointed out in this thread, the only problem I have with this policy is that sometimes a person doesn't have time to wait as he might need a phone/tablet/laptop urgently. And if a defective item is received in this case, then I would like my money back as I would have to pick up a replacement urgently from a B&M store.