Nothing happens without your say-so, and everything is reversible
Anything they control that triggers "at the beginning of your upkeep" or similar will trigger during their upkeep step, and they'll eventually draw a card for their draw step
21 Phabine, Boss's Confidant Get Those Parley Triggers Going Parley is an underrated mechanic in which each player reveals the top card of their library, causing you to gain different benefits based upon the types of cards revealed
It's also great for new players because it's so simple to navigate any given Commander match when all you're worried about is red mana and smacking opponents in the face
Unless extreme, these errors dont prevent a card from receiving a high grade
Its pretty rare for new rules to be introduced to accommodate just a single card, but at time of writing Hakbal is the only card that makes multiple creatures explore simultaneously