A "good kid" who breaks the rules isn't a "good kid", it's a bad one. If the parents never found out about the child spending the money, then the blame would not fall on them. However I don't consider this a very likely scenario not only because money doesn't tend to vanish into thin air, but because a responsible parent would monitor their child's spending. They might be able to get away with it for a while, but eventually they'll find out. If they gave them a $5000 check then they can't just forget about it, it doesn't magically vanish from under their noses. Even if they do just give the check and forget about it, it is again, their fault and theirs alone. They caused the scenario in which they couldn't monitor the child's spending. They can't assume the child will act responsibly; they need to monitor their spending. Kids aren't the exact molds their parents have shaped, but they should at least be taught basic survival skills, such as the ability to spend money responsibly.

Then take away that kids computer and all technology, and ground them for a month.

These problems were solved by previous generations, when did parents become such pussies?

When my generation was growing up (and I'm only 29), if we acted up we were expecting a beating at home... And we didn't get our own computer, TV and iPad or console...

That's extremely true, but at any rate, I can't see any way around the fact that the actions of their child and the use of their credit card are more their responsibility than the server owner's. (Even if they don't control their child, neither does a random Minecraft server owner!)