So which supernatural abilities are cheats and which are win conditions?
That's a great question. In general, I think each attraction will have a Witchlight Hand who tells the
markscustomers, "Don't cheat," gives an example or two, and then leaves it at that. Some of the attractions have ordinary (chaotic neutral) goblins as attendants/referees, and those have a passive Perception of
9 -- I plan to have other customers cheating be noticed by the PCs to make sure they're aware they can try, too!
I think
obvious cheating is definitely bad and, even if the PCs get away with it, the mood of the Carnival will alter down. However, ingenious, entertaining, subtle cheating, even if noticed by attendees, would not. The whole point of the Carnival is to entertain the carnival-goers, after all, and if the PCs are entertaining passers-by, then, by faerie tale logic*, they should be allowed to win. They are giving the crowd entertainment, after all -- it's only "fair" they get something in return.
*
Faerie Tale Logic: There are three rules:
-- The
rule of reciprocity states that when a friend, an enemy, or stranger offers you a gift, you are obliged to accept it and offer something of comparable value (be it a gift or a service) in return. Such reciprocation need not happen immediately.
-- The
rule of hospitality states that when a friend, an enemy, or stranger enters your home, you are expected to be gracious and accommodating to them until such time as they prove, by their words or actions, as undeserving of such hospitality.
-- The
rule of ownership states that you must not steal from a friend, an enemy, or a stranger. To take something that does not belong to you without the rightful owner's permission is an unforgivable breach of etiquette.
Obviously, there's caveats. If a pixie steals something from you, but leaves you with a gift in return (a thing they crafted, or what they consider to be a marvellous joke or story), then it's "not really stealing." The Feywild itself (in my game) enforces these rules to an extent -- inveterate thieves will find their "luck" turning sour relatively quickly, until "equilibrium" has been restored (i.e., they have "suffered enough," by the estimation of the Fey Powers.)
EDIT: Also note, the definition of "a return gift" varies tremendously based on the alignment and the power level of the faerie gifter...