It looks like each game cartridge has an unique serial number. Nintendo could easily blacklist everything that touched a specific serial, because they can see from the telemetry something like 500 consoles ran the same cartridge in a day, immediately raising red flags

Considering the non-security of the Wii u ("ah, you say you have a ticket for a game? Sure, feel free to download from the servers, I trust you, don't need to verify that"), I'd assume that until a serial isn't blacklisted, the console would automatically download updates as if it was original

Seems like multiple games are swapped by removing the cartridge and reinserting it, would swap to the next title. So, 3-4 titles max or it will be annoying