I have very little experience with Performance.

REI is technically a consumer owned non-profit cooperative, and thus one would expect pro-consumer policies.

My guess is that the REI return policy costs them almost NOTHING. The reason is that only a small portion of the items are returned in damaged condition. Maybe 1%? So they still make their sales margin on 99% of their merchandise. Of those 1% returns, most of them are resold at cost, so the company still isn't losing big bucks.

And happy customers make for a good business, and good marketing.