For events run at competitive or professional rules enforcement level, giving someone advice in a match is covered in the Magic Infraction Procedure Guide. It falls under the category ‘Tournament Error – Outside Assistance’ and the associated penalty is a match loss. This match loss is given to the player that either sought advice from someone outside the match or the player who gave advice to someone in another match (i.e., you can’t force a match loss on a player who’s in a match by giving them advice; you’ll just earn a match loss for yourself). In instances where the person is not currently in a match, but is a player in the event, the penalty is applied to that player’s next round.

Hopefully none of what was stated above comes as a surprise and doesn’t seem particularly harsh. The reasoning for this is that players in a tournament are expected to play their own games and make their own decisions; the tournament isn’t meant to test a player’s ability to follow directions.

An important thing to keep in mind is that this penalty can and will be applied for seemingly innocent chatter. It is very easy to accidentally provide play advice or information about a game unintentionally. It is recommended that players that are not in a match be very careful about what they say and do not engage in conversation with players about their game. What seems like an innocent comment or joke may have unintended significance and lead to a severe penalty. It’s best to simply remain silent when watching a match.

While there is not a specific penalty for this behavior at regular rules enforcement level events like FNM, it is still an unwanted behavior that must be avoided.