#1, not needed. /msg nick stop acting a fool or /ms send nick stop acting a fool. All this cmd will do is waste anopes resources doing something you are completely capable. Of doing yourself. If you want canned warnings, might I suggest you learn the scripting language of your client of choice. Mark them with oinfo.
Second, why would you allow abusive users to stay connected to your network? They have obviously displayed a lack of respect for your rules so why would you feel compelled to respect them by allowing them to stay?
#2 perhaps convenient on poorly configured nets that allow opermasks to be *@*, other wise gline/akill the operhost for x time and they can't oper anyway.