heres my question. how do they know if the damage is done intentionally or not? many companies and makers says they will fix all damaged knives as long as is not done intentionally, in other words, abused. But how can they know? what if I just had it for a long time?
heres how I look at it.
Busse combat knows how their knives leave the shop. if a knifes edge, spine, or handle has been modified, they'll know wether it was there work or not.
when a knife breaks, you can see where the stresses were concentrated, and get a rough idea of how the knife was broken, and what caused it to break.
if the knife is modified, and the break was centered on the modification - you can look at it and get an idea of whether it coincidentally broke there, or if the modification was the direct specific cause of failure.
example: if you cut notches out the top of the knife for thumb ramps with a dremel and you get it red hot on every one. the knife breaks on one of those spots, and at the top of the fractured part of the knife, you can see the steel blackened and the heat treatment visibly damaged. You, the person who modified, caused a weak spot in the knife that was not there from the busse factory that caused its failure. since the knife broke on the damaged area, chances are that your modification caused the breakage.
another example: I took a NICK and modified it down to a regular sized knife. that meant cutting away almost 40% of the knifes blade. The knife I ended up with was never tested by busse combat. they didn't do lateral tests, destruction tests, they didnt grind the bevels. they have NO way of knowing if my new design is strong enough to take daily stresses. thus, if that blade broke (having NO resemblance to the blade profile it was made of), it can be assumed that my modifications were to blame.
another example (last one): you modify the handle, taking off the butt of the knife and thinning out the top and bottom. When you go to pry with the knife, the tip breaks off. chances are - your modifications had nothing to do with the breakage, because that part of the knife was factory in every way, and if there was heat damage at the butt. it shouldn't have traveled to the tip if you were trying to not get it to hot in the first place.
so... in short - if your modification breaks the knife, chances are it shouldn't be covered by the warranty. if your knife breaks and it had nothing to do with your modifications - it is at busse's descresion to replace it. they tend to be very big on customer satisfaction, so chances are it will be replaced, but if your mods are obviously to blame for the breakage - you shouldn't send it in for warranty in the first place.