I like living in a place where my kids can play in the front yard without non-stop surveillance. Every parent has had a kid run out of sight in the back yard, a store, or the mall. The idea that jerks like you say things like that every time something bad happens to someone's child really pisses me off.
While thezach's comment does come across as being from a jerk, keep in mind too the same reaction applies to "every parent" who expects the rest of society to curtail every possible activity that might hurt their unsupervised child.
Does anybody really think it's a rational argument to make, that this guy _shouldn't_ buy and drive his own fire truck because it's a risk to "the children"?
Kids bike and play in neighborhood streets. Surely you recognize that some untrained guy driving a massive firetruck up and down that street just to get groceries is a problem.
I'll agree with you that "watch your kids 24/7" is unfeasible. But I did think of something that would get the same results in this case: teach your kids to respect the property of others. It always confused me that, for example, trampoline owners could get in trouble because local children, without the permission of the owner, came over to jump on it and fell off and broke a bone. The kids are at fault, and that reflects on their parents.
This is long established common law. Just because it is your property, you cannot escape your obligation to mitigate obvious hazards, particularly where children are involved. So hanging a tree swing that is unsafe and snaps, injuring a child playing on it, still creates liability for you even though the child was trespassing.
My kids know not to run out into traffic and they know to stay at my side when walking in a parking lot because they have been told over and over that it is a dangerous place (and punished for doing otherwise). But, no matter how well they know it if I pull into a parking lot of a restaurant and Grandma and Grandpa are standing there, the kids run for them in excitement. They are smart for their age, but they are still little kids.
That's why public safety has to be a balance between rights and responsibilities that may not always seem "fair" to some. I can not say what my kids would do if I pulled into that cul-de-sac and they hopped out of the car and saw a firetruck sitting right there. I know I would not want any old belligerent "its-my-right-of-way" guy driving that thing but I doubt there will be some sort of epidemic of firetruck driving in my area any time soon.
(As a farmer I think I come to this with a different perspective than most. I work with heavy equipment all the time in a yard where my kids run around, but in a remote yard with just your kids it is pretty easy to do a head-count before you move something.)