My understanding is that each Switch cartridge has a unique key or certificate. People have begun dumping the cartridge ROMs (including certificate) and sharing

My understanding is that each Switch cartridge has a unique key or certificate. People have begun dumping the cartridge ROMs (including certificate) and sharing these online or burning them to writable carts. Nintendo is blocking these keys from online play. The upset seems to be over the very narrow case where someone dumps a ROM, shares it widely enough that Nintendo blocks it, then sells the genuine progenitor cartridge to an unwitting customer. I can’t see that happening too often, it only affects online play, and it’s the exact same risk someone takes buying a used console (which are frequently blocked from online play for a number of TOS violations). I’m fine with this. While I am generally against DRM and over-reaching copy protection mechanisms, I think this is reasonable. Especially in the context of online play.