You need to watch the video before you make any statements regarding it. I've been on a protest committee (2009 Hobie Tiger North Americans) where a skipper got speared at a mark rounding, so that type of injury is not unheard of. A Tiger's pole is a lot shorter than that lance on the ARC-20.

Bad things happen in the blink of an eye, when you least expect them to. All you can do as an organizer is be prepared. Explicitly invoking the Racing Rules of Sailing, having the appropriate insurance and having a written safety plan go a long way towards mitigating the accusation of negligence in a lawsuit.