What do you mean by complete control? My 17 yo racked up $20 in DLC in a single day... Since minors are not responsible for paying the bills, I can understand why the adult responsible for the account has to sign off on that.
Apple is now refunding millions to parents for unauthorized purchases, so I suspect they'll be modifying their store/in-app purchases as well. My older daughter is among them... my 12-yr-old granddaughter bought $250 worth of music one month.
The FTC is suing Amazon over unauthorized in-app purchases.
The fact is, companies are limiting their liability by requiring parents conscientiously agree to pay for whatever their kids do. I would think the only people who would take issue with this are the minors who object to being subjected to parental control. But until they are paying for their own phone bills, that's the way it goes.