Your entire post reads as a cheap appeal to emotion, rather than a balanced view of app purchase methods on mobile devices.

Let's turn this around for a second. Why are parents letting children use their very expensive and unlimited purchasing power mobile devices without supervision? If the kids have their own phones, why are they linked to their parent's account for purchases, instead of using the (very cool) allowance feature that is built into the store?

There are a number of solutions to this problem, but arbitrarily deciding how many clicks away a purchase has to be or somesuch is near the bottom of the list.