[ffcmike]

I'm certain that this is a seperate account accessable by another person,
and that they've simply recieved cards from the primary account.

I don't think this is fair but then if you had Pokemon in both versions Red and Blue i'm sure you'd transfer yourself over the starters you decided against choosing in the initial game aswell as any other you wouldn't otherwise be able to obtain,
you could say it's part of the game.

It could easily be made so people cannot obtain cards from a matching IP if need be,
something else that comes to mind is the possibility of forcing cards to be traded rather than dropped and only allowing the trade of same-level cards.