The simple fact of the matter is that there is no "right answer' here. Our track races 1/8 e-buggy and only allows fellow racers to marshall and absolutely no kids are allowed to marshall 1/8 scale. Honestly people worry about their size but my 1/10 scale 4 wheel drive with a 6.5 could take you out just as quick if it hits you right and its faster. Disclaimers dont work. How do I know? Easy. A guy at a past track went out. Marshalled with flip flops on and a car ripped his nail off. He sued the track and it shut down. Everytime you marshall in this hobby you take a risk. Its the people who take advantage of that are at fault. Its the people who are totally fine until something happens to them. Then their understanding just flies out the window. This type of deal happens all the time in retail and other places as well. Me personally I get more anxious on an outdoor track where 1/8 scales can get up to speed then I ever will in a indoor track. My closest encounter to getting hit in the head was outdoors. To me it's just an excuse.