I find this situation interesting. The power to mute is more than likely in responsible hands, but I think it's only fair that they at least
inform the user that is being silenced that there is a reason why they're silencing them and that ..they are indeed going to be muted for a bit. Is there a timelimit on being silenced? Does it timeout after a day? Those are just idle questions. Anyways, I don't think the person was hiding behind their power user status - probably didn't think. Key word, think. If you must mute, do so.. but at least be kind enough to inform the user. Just an opinion.