Bullet the Blue Sky
The family made a decision. Maybe not one I would make, but whatever. Clearly they have an "influencer" vibe.
But I do think the race organizers made a mistake to sanction their stunt. They should have said sorry, we have a minimum age and a course closure time (~7 hours). I'm not sure why they would approve it or what they gain from it as a race organization - other than controversy.
Best approach probably would've been to say no, but not make a big deal out of it when the family did it anyway.