[petsfed]

It happened at least after 2013, because I went skiing with a guy who made it a point to return everything he'd ever bought from REI because of a court case he read about. It was a sort of super-boycott.

I chose an extreme case, because the cost is clear, and the consequences are very visible. Obviously, a company's peculiar financial situation will determine the acceptable return-and-refund/replace rate. Every company will have a financially acceptable return rate, and will look for easy fixes to keep their actual rate below that. Barring replace/refund for user modifications is a way to lower the refund/replace rate, without actually decreasing the number of items that get returned. There's still a cost to inspecting devices for user modifications, and that cost may in turn lower the acceptable refund/replace rate, but it does mean the product development people have to spend fewer resources eliminating potential sources of failure

None of this is to say that I think firmware shouldn't be field editable. Just that barring those sorts of things is low-hanging fruit and (in general) pretty easy to sniff out if the device is just bricked, not permanently damaged. I think manufactures could instead enable firmware updating after cutting a particular trace, to the same effect. Thus, the would-be hacker must knowingly physically damage the product in a way that clearly voids the warranty, and then they're free to modify to their heart's content.