The problem comes into play in a Skins match with 3 or 4 players. Two players could "team up" against the other player(s) by conceding putts for each other
Players B &C team up.
Player A has 2 feet for birdie
Player B is 18 feet for bird, Player C is 23 feet for bird.
Player C misses his putt.
Player B's turn. Player C concedes the 18 foot putt to player B!
Player A makes the 2ft putt and the hole is halved with the Skin carrying forward.