Ruling Knowledge of my discard pile

[tulleh]

In the compendium, it says that the game has no knowledge of the cards in your deck, so you can choose to not find a card if a trainer etc... asks you to look for it.

Does this apply for your discard pile? Such as Marley's Request - can I just take back one card, and pretend the others don't exist? I have a feeling I can't because the discard pile is "public"

 

[Amt]

No.
The discard pile is public knowledge. Your deck is not, so that is why you may fail the search of your deck.