Let's start out by saying that KaBar is a very good company - one with a proven track record of standing behind its products. Then, there's Uncle E - who always gives Becker customers the benefit of the doubt. Way far down on the list of factors to consider (as the first two pretty well sums things up) there is the Magnuson–Moss Warranty Act (P.L. 93-637) which is a Federal Law.
As Fal'er correctly references, the failure/defect would need to be causally related to the act or omission that the manufacturer relies upon to disclaim the warranty. In an exaggerated for the purposes of illustration example using automobiles, a manufacturer would be hard pressed to disclaim a warranty on your defective electric window operating motor because you failed to use the proper grade of engine oil or failed to service your engine in accordance with manufacturer's recommendations.
IOW, if the knife's finish develops patina or some cosmetic imperfection after its factory applied protective coating has been removed - me thinks you would not have a viable warranty claim. OTOH, if completely unrelated to the lack of factory applied finish, a catastrophic structural failure occurred through normal use (use for which the product was intended and/or in accordance with an operating/owner's manual), warranty would likely be honored.
I said all of that to say this: KaBar is a very good company - one with a proven track record of standing behind its products. Then, there's Uncle E - who always gives Becker customers the benefit of the doubt.