A problem today with a club assistant. In this case a substitute running the line. Before the game, I gave my usual instructions which include leaving fouls to me, not because I don' t trust them, but because it causes problems. Never had any club official have problems with that instruction and none today. Problem was when he raised his flag and told me a player had called him a cheat and he was 'very offended'. I didn't hear and he didn't think I had. I explained I can only give what I hear, but spoke to the player and told him what would happen if I heard that word. After the game, he berated me for not sending the player off, accusing me of calling him a lier. I explained patiently that wasn't the case and that what I had done was consistent with my pre match instruction. He then played the 'I'm a qualified referee and I would have supported you if you had been my assistant' card. I still think my policy is the only safe one, particularly with substitute officials who don't require any qualification. The alternative seems to me too problematic, but interested if anyone has a different approach ? Clearly if it had been a neutral official, red card no question.