Quoted from Chisox:My question, or dilemma, is am I a negligent parent for allowing my kid to play a dangerous game with possible life altering after effects?
The simple fact that you are asking this question and are concerned enough to seek advice/counsel from neutral outside observers means no, you are not negligent.....you are in fact a kick-ass parent.
As my Aussie friends say, "Good on ya, mate!"
Later,
EV