In-app purchases and children's apps

At the AppNation conference in SF last December, the conventional wisdom of the talks seemed to be that best business model for app developers is free plus in-app purchases.  This makes a lot of sense for regular apps where the user is also the account owner.  Free to get a lot of people to try your app, in-app purchases to present the buying opportunity when your users are in the buying mood.  Brilliant.  But what if the user isn't the account owner?

This model breaks down for children's apps because the app proves its worth to an advocate and not to the buyer.  Even the best kid-sized con-artists advocates have a hard time convincing the same parent to buy an add-on ten different times.  It's better to package those ten things up into a single purchasing decision (think "pro" version) and ease the burden on your little salespeople.