Does collusion with a dealer require pre-meditation? Imagine a situation where you're playing at a table where a dealer sees his hole card when checking for a blackjack. You get all ready to hit that 14 against a 10, when you hear the dealer say: "I wouldn't do that if I were you." You look up puzzled. He adds: "14 might be enough". So you stay. Dealer's hole card winds up being a 6 and he busts. The dealer continues to drop hints to the table after he has checked for a blackjack.
So is this considered collusion? Remember, you don't know this dealer personally. You didn't make a plan with him. You're simply using the info that this dealer is freely giving.