2004-10-04 : Can’t acquire the Ante cards. They are considered still “in the game” as are cards in the library and the graveyard.

2007-05-01 : If you fail to find something, you still exile this.

2007-05-01 : The choice is optional.

2007-09-16 : Can’t acquire cards that are phased out.

2009-10-01 : In a sanctioned event, a card that’s “outside the game” is one that’s in your sideboard. In an unsanctioned event, you may choose any card from your collection.

2009-10-01 : You can’t acquire exiled cards because those cards are still in one of the game’s zones.