In Season 1 Episode 6 - "The Mysterious Card Shop!", when Aichi fights Kourin, Kourin appears to have duplicated Aichi's Royal Paladin Deck.
In Episode 23 - "Fateful Encounter" it was the same in the match between Kourin and Ren however Ren was invited to PSY and Kourin had Ren play using a pre-built deck which was the same she used. as Ren noticed it was because Kourin was seeing a person's true skill as a fighter rather than the strength of their deck.
But i don't recall Aichi, Morikawa or Izaki being invited to PSY rather they found it by accident and even if they were invited, unlike Ren, Aichi had never been in any tournaments so there was really no way for Kourin to know what was in his deck via any broadcasts.
So how did Kourin copy Aichi's deck?