Motorcycle accidents and Player's contracts

In light of Big Ben's recent run in(he's OK, pun intended) with possible severe injuries a lot of ink has been put into whether or not teams should be allowed to protect themselves in a player's contract. The question was asked on the most recent update of Chalk Talk if the Bears made an specfic additions to their player's contracts.

There's a clause in all standard NFL contracts stipulating that players are in breach of their agreements if they are injured "as a result of participation in hazardous activities which involve a significant risk of personal injury and are non-football in nature, including but not limited to skydiving, hang gliding, mountain climbing, auto racing, motorcycling (includes the operation of all types of motorcycles and/or all-terrain vehicles, scuba diving, skiing (water and snow), and/or professional wrestling."

I know Urlacher once stepped into the ring and did a few clothesline in a bit with his friend, Eric Angle and I know Rueben Brown is an avid motorcycle rider, but other than those two I don't know of any player who has or currently does anything that might fall under those restrictions unless you count "dork pounding", in which case Ricky Manning Jr. would apply.