The problem with that model is that if you drive to fast the back falls off due to the weight of the children. To find the proper age to kidnap without the back falling off, use the formula (weight of back+weight of children)/speed of van/length of back
Ok, I'll try only because when I don't kidnap a group they get depressed and that makes the meat stiffer, so I've found it's much better to give them false hope with other kids with them ^-^