Solitaire too. The entire game is based on cards' relative values and matching suits. A player might recognise the connection to other games where a French deck is typically used and use that knowledge to learn several hands used in games of chance. Extremely dangerous, I'm sure you'll agree.

Isn’t that why they stopped adding it in the new games, to avoid a higher rating?

They actually already did change the rating for the virtual console release of Red/Blue. I always thought it was stupid, because the game corner was explicitly run by the bad guys.