While I don't know how much race staff cross over there is, but HFP racing (who Shannon Kurek works for/owns/whatever), puts on a large number of races. In my experience their races and NAS races are equal in quality - bad things happen at every race.
How about tacks on the road at Ironman Wisconsin? A farmer driving his tractor down the road? I could go on, needless to say you can't blame what can't be controlled.
Edit: Actually want my best example - Did a race in Lake Geneva a few years ago (not a Dobbs race), where a biker was hit by a car. Guess who hit the biker? A triathlete who had just finished the race and was wanting to get going.