Leadville...Wow. That looked horrible....I used to organize and manage endurance events, what are the race organizers thinking?? That is nuts, what about the insurance and liability factors? When we ran 100 milers our landowners, public and private knew how many people were traveling through, we were accountable for those numbers and limited the entries.
Several ways to stop all that would be to make it a race that you would have to qualify for...or lottery like the mountain bike races....And they should be limiting the numbers of entries for the space...someone got greedy. If the staging areas and trail and medical aid areas cannot handle the huge crowds then they are putting everyone at risk!