My condolences to his family and the families of the bystanders, but stopping the bikers from participation is a stupid idea, simply reroute certain portions of the rally away from certain villages, far simpler.
Having ridden off-road bikes for a number of years,(a long time ago) I think the biggest problem is the weight of these off road bikes nowadays, 500 and 600 cc TT ype bikes, are difficult enough as it is , but some of these bikes are running What? 1000 1200 cc nowdays, thats a lot of weight when it starts to hop on a corrugated surface, plus the extra weight of supplies that have to be carried with them, water, toolkits etc, you lose that at 120 or 140 , it is hello pearly gates.
Slightly off track, now here is a tough race, i take my hat and socks off to these guys, the Sahara Ultra marathon
http://www.pacesetters.com.my/resource/news/Sahara ultramarathon2007.htm