Jumbled zones don't merely create clientside lag; the server also has to send a ton of exponential player data to players within rendering distance. It's like a hyperbola; for every multiple players interacting, the amount of intimate data multiplies to each of the players in the situation. So if two players interact, the server sends one extra player data to two people (2). If three players, it sends two extra interactions to three players now (6). If 50, it is processing 49*50 for one arbitrary spot (2,450).