Years ago before I had any experience with children I used to think they were awful and would comment to myself that the children are being treated like dogs etc etc. Since having looked after toddlers who have had a habit of just suddenly making a mad dash I totally see the great use for them. If Ash turns out to be a bolter I'll have no worries using one.
I know we can try teach our children to hold hands or things like that but they can be so unpredictable and something catch's there eye and suddenly off they go without warning.
My nephew was a bolter and actually ran off onto a road once suddenly, just let go of my hand and dashed off. Luckily no cars were around.