Je fais un petit up parce que les règles d'Eldritch Moon ont changé la réponse à cette question :
Citation :
714.4 If information about an object in the game would be visible to the player being controlled, it's visible to both that player and the controller of the player. If information about cards outside the game would be visible to the player being controlled, it's visible only to that player, not the controller of the player.
Le Gatherer du Mindslaver a lui aussi été modifié pour refléter ce changement :
Citation :
7/13/2016 Controlling a player doesn’t allow you to look at that player’s sideboard. If an effect instructs that player to choose a card from outside the game, you can’t have that player choose any card.