If you're honest about your reasons and their policy covers the return go for it. If you feel guilty, get store credit and buy something else from them.
It's rei. They'll accept it. I don't think they'll even ask why you're returning it. If they do, just be honest. They mainly ask so they know it's not defective. They'll sell it at they're yearly member sale at discount. You may be doing a poor hiker a favor.
