You're probably right that legal risk is a consideration; or the perception of risk; or both. But frames of all materials get damaged, and warranty might help but usually doesn't. Repairing a frame could/should be cheaper to the rider than replacing a frame, in many cases, especially when there are probably half a dozen new standards in place that mean a bunch of your parts won't swap to a new frame anyway. And faster than dealing with most warranty departments. And less wasteful. I'd be interested to know what repair options are out there.
I was pretty happy to have a $300 fix on a $3000 frame and get back on the trail in a couple of days!