Lautieri v. Bae,17 Mass. L. Rep. 4 (2003). It was a Massachusetts case but not a Supreme Court case as best I can tell. Regardless, the provider was found grossly negligent where, in the bicycling leg of a triathlon, the race director failed to heed a number of industry safety standards regarding intersections – leaving the intersection at which the incident occurred open to automobile traffic, uncontrolled by police or volunteers, with no warning signage for contestants or drivers, and unmonitored.

~~ k