I agree, its totally reasonable. That said, I'll probably shop there less.
I generally waited for the %20 off sale at REI to make bigger purchases on things I wasn't totally confident would last (neo air xtherm, ultra distance trekking poles etc.) I have friends who work at REI, and I genuinely think they are an excellent co-op even if they don't offer the ultimate in nerdy technical UL gear. I hope this doesn't negatively effect business, but I wouldn't be surprised if a lot of other folks also take their business elsewhere.
I know that a lot of people on these forums have already arrived at this attitude, but I'm trying to be more conscious about the long term durability of my gear. On a practical level, I can't really afford replacing stuff like broken trekking poles etc. But more importantly, its just wasteful and bad for the earth to buy gear thats basically disposable. I think a certain amount of UL gear nerdery is acceptable, but I don't want to be a natural resource vampire. Taking this attitude a step further would suggest making mainly second hand purchases, which may very well be the route that I take. For now, I just bring this up to suggest that unlimited return policies might encourage bad consumer habits, and create a win/lose situation for consumers/the environment.
Oh, and if you're wondering the xtherm has been great, and I'd buy it again without the lifetime warranty. The one pad solution.