the legitimate promotions of this sort; and walmart, as big and as greedy as they are, are still most certainly doing this on the ‘up and up’, the donations are tracked separately and separate from the revenue stream. it just gets passed-through to the charity. no tax deduction shenanigans involved. walmart already has other ‘legal’ loopholes and accounting tricks to use to lower their tax burden, they don’t have to do something blatantly obvious and easy to track that isn’t nearly as ‘effective’ at it.