Is anyone allowed to direct traffic in case of emergencies in Ontario?

I was recently told at a first-aid cl that one way to keep bystanders occupied was to have them direct traffic. However, I also remember being told following a car accident a number of years ago that only someone who was actually qualified for traffic control was allowed to direct traffic (anyone can place cones/flares around their vehicles, but not instruct other drivers on how to detour around it). This makes sense based on liability - I don't really have any qualifications other than common sense for this, but I can't seem to find any information confirming one or the other. Does anyone know for certain what the rules in Ontario are?