They won't raise prices. But the dividend that I recieve each year will go down. They won't become less competetive. REI has a solid customer base for a reason, despite their problems.
If you return a product that you didn't buy at REI, you are stealing. Period. It gets murkier when you return stuff that you actually bought there. I don't sleep well if I do something inethical, and if I return gear after trashing it in the mountains I feel it is inethical.