Rules for throwing knives
1. Don't. Please.
2. If you must, first practice a LONG time (i.e., for many years) with non-living targets and make sure you miss them EVERY time.
3. Keep in mind that the idea is to MISS the person in the middle.
4. Keep knife-throwing confined to the circus. Don't do it at work or school, and especially not at home or church ... with physical OR verbal knives.
5. Before you start, allow your intended target see you practice before deciding whether to volunteer, and ALWAYS get such informed consent (see rule number 4). The legal ramifications could be life-long. Or in certain instances, life-short.