In the upcoming set 'War of the Spark' there is the Planeswalker Karn, the Great Creator. His -2 ability reads as:
-2: You may choose an artifact card you own from outside the game or in exile, reveal that card and add it to your hand
Now my question is, in a sealed tournament, like the Prerelease, is a player allowed to also choose cards from outside his sealed cardpool, or only out of the cards therein. Does anyone know any rulings on stuff like that?