Chelsea dropped the case against Mata, pursuing with racist claim against Mikel. Seems like it should be pretty clear. All the assistants heard the alleged conversation. If they side with the referee's version of events, Chelsea will have no leg to stand on and frankly should be punished. Can they be punished? It strikes me, admittedly with no backing whatsoever, as a grievance borne out of frustration against the Terry situation and the performance of the ref. If the ref did make a racist remark, then his career is probably over. Why would he take that risk?