For the purposes of this debate, a 'Social Court' is a method of holding friends to account for legal, but socially undesirable behaviour.
Any friend within the a friendship group may bring a charge against another, and class action charges are permissible. For example Friend A (or a collection of Friends) could bring a charge against Friend B for missing a dinner reservation or cheating on a mutual friend.
The exact nature of the proceedings would be decided and codified by the group. These rulings are not legally binding, and have no real legal weight.