A Warranty is really about a Name. If you purchase screwdriver at a Flea Market that has no name on it you buy it with a different view of performance than if you go into Sears and purchase a set of Craftsman screwdrivers - becuase of the name.
When a Maker puts his name on a product he is selling not only the product but his name with it. We all, either through paid Advertising or verbal recommendation, have different views on different products due to the name on them. Most guys won't argue that Black & Decker hand tools are better than DeWalt, both make Drills and Recip Saws, but DeWalt makes them different and due to Advertising and word of mouth most guys would rather own a DeWalt.
When a Maker wants to use his name to sell he must also accept that his name will stay on the product no matter who buys it in the future and thus that buyer who makes his decision on whether to purchase this product- due to the name.
When a Maker warrants his product (knife, tool, etc) to only the Original Buyer - he is stacking the deck in his own favor, making the original Buyer pay for the name but not wanting to accept responsibilty for the product should someone else own it. Having his Cake and eating it too.
This is not about abuse per se, I know it occurs and that should be handled on a case by case basis, sometimes a Maker has to face that. This is about the product in general - for a knife it could be Handle Shrinkage, Poor Heat Treat, Scales falling off, Thong Hole shrinking

- etc.
A Maker publically saying that he will only warrant a knife to the person that purchased it from him - cutting his own throat if you ask me.