Can you check the effect of a yugioh card in a duel?

When someone plays a yugioh card like a trap card or a magic card. Are you allowed to check the effect to make sure they are not just lieing? and if someone play an effect card are you allowed to check the effect to? IF not is there anyway to tell if they are not lieing?

Public Comments

1. Yes you can. Hope this helps! :D
2. yes but you must ask the opponent first. If someone lies they will get disqualified from the round or tournament.
3. Yes. You must ask them before you pick up their card. After reading the card, if there is a disagreement about the way the effect works/doesnt work, then you can ask a judge. If they dont know, then they can check the official rulings for you.
4. you are allowed to look at every face up card on your opponents side of the field, and every single card in your opponents graveyard. the only cards you cannot look at are the cards that are face down on the field, the cards in his/her hand, and the cards in his/her deck.
5. you may but only if you ask your opponent first