"Look, when you send your cell phone in for warranty repairs we may _occassionally_ send one back where the mainboard is replaced with thermite that will ignite the first time you connect it to a charger. If we do that without telling you, we're not liable for your house burning down because our warranty document says we don't cover that. Thanks for understanding. HTH HAND."
I'm sure that will totally fly in a court. Not one with real lawyers or jurists, but _a_ court.
This wasn't a mistake or freak accident. This was a reasonably foreseeable outcome of EVGA's decisions. They could have prevented it at multiple steps along the way. The only things the customer could have done to avoid this (i.e., replace the cables) they were directly advised not to do by EVGA.
Who could have prevent this happening, and how?
The end user could have prevented it by... not making use of the warranty he was entitled to? Ignoring EVGA's advice to keep his cables and instead replace them at his own expense without even knowing that the cables were in fact different?
EVGA could have prevented it by not sending him a PSU with a different pinout, by sending him the appropriate cables for the PSU he was sent, by providing a warning that the PSU was incompatible with previous cables and telling him to replace them, by...