... though maybe the human powered cyclists could take to wearing spikes... as a warning. Don’t mess around with Spikes ‘n’ Spokes. One idea, don’t know how good or bad it would be. The spiky bikers might attract more attacks, not less, by ground based dudes with ‘tudes. No easy answer down this road.
WWJD? I dunno. Other than pray before and while riding. Even peaceniks have some sort of limit.
Mount a sharp spear to the handlebars and no one will stand in the middle of the bike path obstructing your way. It's harder for them to hit a moving target.