I guess HeluvaSkier, DD223 and AMike said it all for those racing. There might be some differences based on good/bad personal experience with particular bindings or generally.
I agree that there are too many skiers using too high settings but I have to repeat what is paralelly being discussed here: http://forums.epicski.com/showthread.php?t=29845
(my post #68 vs. #69 and 81 vs. 79...)
in more serious racing the speeds, snow conditions and resulting forces influencing the way the bindings operate are different to the extent that justifies higher settings.
Most people have probably never seen a "race chart" (racers don´t need a chart, do they) but I have one. It´s for junior racers and was published 10 years ago but except shorter skis (less leverage) there´s not much change (maybe more snowmaking hence harder snow though not so deep ruts).
It operates with slightly different setting at the toe and heel.
a 14-year old boy needs DIN 5 when skiing free but DIN 7-8/toe and 8-9/heel in GS
a 17-18-year old has DIN 8 but 12/toe and 13-14/heel in GS and 14/toe and 14-16/heel in DH.
(Girls/women need 1-2 less, heavy and physically very strong more, and vice versa. Let´s not forget the biological age which may differ by 3 years up or down in 11-year-old girls and by 3.6 years in 13-year-old boys according to Swiss studies.
If Atomicman joins the discussion he could tell us what his sons use, the older is, afaik, a pretty big guy.)
Which means that you could/should set almost twice as high for a race than for "civil" free skiing.
I can be happy with DIN 8 when demoing some allmountain skis or on slalom skis skiing free, and with 9.5 on GS skis used only for free skiing. I use 10.5-11 when training GS in average conditions and I increase the forward pressure to prevent "counterflex release" (called "the flex effect" by Vermontskisafety). For a race I go up to 13-14/heel and maybe 13/toe but never forget to go down when it´s over. I don´t find such a differentiation hazardous. To race on 9.5 and wonder why it pops off would be ridiculous, though.
As I remember, in international tests with excellent skiers including some top ex-racers the most common setting was approximately 9.5. DIN 11 was an exception and I don´t remember having seen 12. Fact is you don´t test racestock skis in gates and the slope is mostly well groomed.