At least
something has to be said in this being a rural area. I live in a rural-ish area of Colorad, and my parents had 6-20 acres in our "backyard." They couldn't be expected to watch us 24/7, and they couldn't be expected to follow us everywhere we went. Certainly at 4 years old.. they would've been watching us.. but at 6 or 7? Me and my sister were playing "story" where I was the knight and she the princess.. galloping all over the property by ourselves. An accident
could have happened, and I wouldn't have chalked it up to bad parenting. I think they trusted us to be somewhat responsible. Likewise, I was riding my bicycle down our dirt road at a pretty young age -- it's hard to say how responsible both the child and the parents were. The parents might've been unfortuntely lulled into believing their child was more responsible than he was.
However, it's also hard for me to see letting a 4 year old, even a 10 year old.. sit on something thats got red-hot tailpipes, an explosive liquid, and toxic fumes. That's something you gotta be like .. 16 for.