Hate to be the devil's advocate here, especially since I'm one of the responsible riders that this directly affects, but don't they block off the gardener for some kind of run for some cure every year?
The DVP and Gardiner are closed properly as part of the Ride for Heart every year. You can apply for permits and pay police to safely close roads.
If the riders really wanted to increase awareness, a few calls to media and a line of bikes riding the speed limit with proper spacing kilometres long circling the highways around the city would probably get air time. They had quite a few bikes, if they wanted to, they could have done something good. Unfortunately this group of people just wants to be *****.