They could try to financially ruin the people working-on and hosting Pretendo with legal procedures, but there is a significant risk a case would move swiftly because it's clear-cut that Pretendo is preserving functionality that Nintendo no longer offers, for games Nintendo no longer sells. De-Facto abandonwares.
Unless Pretendo hands out decryption keys or sells Nintendo assets then there's no risk with them shutting down. As far as I'm aware they're just making their own network strictly for those consoles. It is up to the user to join that network through their own hacked console.
They could try to financially ruin the people working-on and hosting Pretendo with legal procedures, but there is a significant risk a case would move swiftly because it's clear-cut that Pretendo is preserving functionality that Nintendo no longer offers, for games Nintendo no longer sells. De-Facto abandonwares.
Unless Pretendo hands out decryption keys or sells Nintendo assets then there's no risk with them shutting down. As far as I'm aware they're just making their own network strictly for those consoles. It is up to the user to join that network through their own hacked console.