The lesson is when a bike is traveling 80km+ stay where you are don't run like a deer in headlights. A totally avoidable crash that kills a season.
Now the race organizers could also take a bit more effort to rope off sections where speeds are like this. They can't barrier a 250km stage but circling tighter in to a town to get more spectators (which is good for the sport) makes it a bit easier to deal with since it's less area to make safe.
Overall the 2012 edition of the Tour of Flanders was a fun race to watch. I though the break might stick and Tom played his cards right. Sucks to see two riders out because of crashes with spectators which could have been avoided.