Fans have become increasingly brazen and inched dangerously close to the riders competing in big stage races, like the Tour de France. This is particularity troublesome when the riders are crawling up big mountains at slower speeds. Fans feel like it's acceptable to break there concentration and running alongside, etc.
Yesterday this happened during stage 18. Watch for the dude in a blue shirt. He takes crowd control into his own hands as American rider Tejay Van Garderen soldiers on up the hill, almost winning the stage.