Good point Mace. Same with the caution about filling the tank. As well as all the other points of course. There is a lot more to it than just the driving. Does anyone really think that kids of 4 to 7 year olds NEED to start learning to drive? At that age the first thing they need is exercise, not learning to sit down for their fun.
In many countries it would be illegal for them to even be on the machine. Those four boys in Iowa would still be alive if they had not been allowed to drive it. The driver who failed to stop (could he stop, or was his weight too much and he was pushed over the line?) bears responsibility for their deaths, but were they legally driving on the road?
Are there any laws in the various US States about how old kids have to be before they are allowed to travel on agricultural equipment, and to drive it? I do not have the info to hand about various countries over here, I just know there are age limits somewhere in the teens, and parents have been prosecuted for permitting under age use, especially following accidents. And yes, I did drive a little grey Fergie when I was about 10, so did my brother who was 18 months younger. Always under direct supervision, and always in first gear.