Might I humbly suggest that parents not share their iTunes account’s password with their minor children and, for that matter, with their children period, just as they would hopefully not give their children permission to use their credit cards or permission to drive the family car.  The iTunes account password is, after all, linked to one of their credit cards, and their children are, well, children.

Might I humbly suggest that parents not share their iTunes account’s password with their minor children

From the Washington Post Article;

“After a password is inserted, Apple allows a 15-minute window for purchases and downloads without having to reenter the password.”

No password required.

Well, that will be easy enough for Apple to fix, probably by simply using a log-out button that lets you log-out without the fifteen minute delay.

As far as the Iphone goes, there is an option to not allow in-app purchases. This feature can be locked by a four digit self selected code further limiting in-app purchases.
If you are letting your children use your electronics then the parent should understand the gadget and it’s features first. Where is the account ability.

“(kid + sofa)coffee table = Computerized Axial Tomography”

At least while your kids are running up your credit cards, they aren’t giving away any of your personal information to developers and publishers.

Bosco:  You’ve finally identified a clear advantage of Android’s Market Place:  It doesn’t work to sell apps, so one is safe from one’s kids running up large bill, though your children’s personal info will be lost to Google.

Perhaps, Google will expunge their data, once you notify them that your children are minors, but alas, once Google has passed their info on to marketers, which, I imagine, happens very quickly, there will be no getting it back.