Originally Posted by mcnbns
I don't think they should warrant anything against leaks other than if the block itself leaks somewhere (due to a defect or something). Most of the time it's user error and Dangerden/Sapphire/whoever shouldn't be held accountable for n00bs that don't know how to water cool.
Still, it would be next to impossible for whoever it was that sold the block to prove that it was the user, so the seller would end up footing the bill.
The Toyota analogy is good, but it isn't generally the car owner that's installing the supercharger, I would guess. Toyota knows exactly what's been done to the car before they give the customer a warrantee. The water block vendor doesn't know how good the installation of its product on the motherboard will be.