>>32264591Yes, cards that let you "search" for something in the deck are allowed to fail. Even if you have looked through your deck before, the deck is still not considered public knowledge, so searches are allowed to fail since you can't say for sure that a card isn't in the deck using just public knowledge.
The hand is also not public knowledge, which is why you can use Exeggcute's Propagation ability as many times as you want during your turn, despite the ability saying that you only can use it once. Using just public knowledge, you can't say for sure that an Exeggcute picked up this turn is the same as the one discarded right after, even if you (theoretically) were to only have an Exeggcute you just picked up in your hand.
But the playfield and discard pile are both public knowledge, which means that you can't do things that have no effect there. For example, you can't play Energy Switch when you have no Energy attached to any of your Pokémon, since you already know it'll do nothing.
This has been an accidental PTCG lesson about knowledge. Stay wise, FUGlings.