Pirated Gameboy cartridges were everywhere during that time, some were sold as legit by shops.Some creepy-ass photos...
...Yeah I'm not a fan of Nintendo's overly zealous efforts in stopping piracy. Not necessarily referring to this case, but more in general. Or what they perceive to be violations of IP rights, like shutting down that fanmade Metroid game or having people remove tourney ARMS footage. Way to kill free advertising for your games, there :/
Save states deleted mere months after playing ... Imagine collecting video games and then finding out years later that your whole collection was fake, I was heart broken. All my GB and GBA collections were fake.