Much of the warranty repair I've encountered has been from users deciding to tinker with things they have no experience with. Buying a brand new rifle and immediately doing a "pro" tune,lol usually cranking every adjustment the gun has. They then send the gun back saying they haven't done anything to it. In some cases a used rifle may include GKW, "God Knows What" type of modifying therefore making a warranty void. From the manufacturer standpoint I don't blame them for wanting to inspect the product before allowing the warranty to extend.
While I'm new to the air gun world (and HAVEN'T done much "adjusting"!), what is said above, is absolutely correct in the automotive/motorcycle world also. So I have no doubt that similar hands attempt similar "adjustments" on air guns, that have NO business doing so. They they try others help, and because of the original comment, they "F" that up too. And what I've seen on airgun forums, IS NO different. Example - A person just bought new rifle - places a question up on an airgun forum board..."I just bought a new xxx, xxx rifle. It should be here tomorrow. What can I do to it to xxxx, or, what can be bought to add to make it doxxx ?" "WTF" ? the new owner hasn't even had it in his/her hands yet, and they THINK, that they know better than the manufacturer and or dealer. Or, just as bad, the person that's been a little lucky as his/her adjustments and they also, think that turning every knob on the gun NEEDS to be done to "suit" them. Again, "WTF" ?
So now, last ditch effort to correct the given problem(s), (caused by said owner), they contact either the dealer the manufacturer, and do their best to talk around the problem so the person on the other end of the phone "hopefully" doesn't see what actually...happened. Funny thing...the manufacturers / dealers have heard it all. All of the problems, all of the excuses, all of the "no, I didn't try that", when in fact, THAT"S what caused the problem, and the only thing that could have caused "that" problem.
I know, some years back, I was one of the guys on the other...end of the phone ! You learn to spot the frauds / tinkerers / "customizers" quickly..! Funny, soortly, it's NOT their fault, it came that way..!?
Mike