That’s what I’m always wondering with these kind of projects. I actually took a second look to consider backing it, but the reward tier is steep... I was considering the cart and writer, but that’s a lot of money for something in a legal grey area. I still might donate a bit just to support the cause though.
According to Nintendo they're completely illegal as is all sorts of things like making a backup of your own carts. The law is very clear that Nintendo is full of BS here but that doesn't stop them from making bogus claims to scare people. They might even send you a C&D and follow up with legal action. I'd love to see them go that far with something like this that would seem to be totally legal and with enough interest to get 3rd parties involved. EFF would wipe the floor with them.