No, it's not covered under the auto insurance policy of one of the perpetrators (as arising "directly or indirectly" from the use of an automobile), per Canada's supreme court, reversing a lower court. The supposed trigger for coverage found by the lower court was that one of the miscreants "transported rocks to the overpass in the back of his truck". In a separate case, the high court also ruled that a hunting accident is not brought within the terms of auto insurance coverage just because the hunter's headlights were illuminating possible game (which turned out to be a fellow hunter). PoL contributor David Rossmiller has details.