Well that is their policy.
But, that's the thing about policies.
It's really Benchmades choice as to when they should enforce their policy or when they should not enforce their policy.
If the custom scales are pretty close to the original design and all the original hardware is used.
They will most likely honor the warranty.
If the custom scales are a radical change from the original and none of the original hardware is used.
They might not.
I have had several customers of mine ask BM this very question. Both before and after purchasing custom scales from me.
So far, so good!
However, it really is up to BM as to weather they honor the warranty or not.
I have no knowledge of any replacement scales becoming available through BM for customers to buy and install themselves.
Now that would suprise me.