Two cents. Some kind of honor system or common sense has kept most of the thousands of spectators and their stuff from interfering or there would be a lot more incidents. How about this? Riders on electric motorcycles near each side of the road 15-30 seconds ahead of the pack. Quiet with no exhaust. Attached to and extending a few feet or metres to the left and right of the bike is something stiffer than a pool noodle that won't really hurt but still means business to clear the edge of the road. Since most people are focused on the riders and then the aftermath spectacle of the crash it is easier for the one that caused the crash to escape. Make it OK for other spectators to detain or deter the idiot who is still too close to the road