5% of the population are sociopaths, and 1% are psychopaths. Psychopaths get enjoyment from peoples suffering. So in Australia we have approx 250,000 psychos in the community. At an AFL crowd of 50,000 there would be 500 psychos at the game. Not to mention the 2,500 sociopaths.
Anyone who doesnt keep their kids in their sight at all times out in public is nuts.