DISCLAIMER: Single with no Kids but regularly have to help parents with sorting our their iOS stuff for their KIDS
I personally think allowing the in App Purchases a 15 minute window is kinda a step back from the constantly requiring a password and it adds another thing for parents to worry about, unless you are somewhat tech savy and setup restrictions then this is a problem for most parents not just those lazy inattentive parents a previous poster referred to.
Devils Advocate time:
This is the reason why the terms and conditions exist (unfortunately lawyers are involved and they are really really wordy) for instance the statements below are extracted from the early parts of the
Australian Terms and Conditions for iTunes accounts (the same bits exist mostly word for word in the
US version too), so if every user actually read the first bit of T&Cs then they would know all about the purchase window and also how to enable restrictions.
So please encourage people to at least skim the T&Cs because it will save us all from headaches!!
This iTunes Service is available for individuals aged 13 years or older. If you are 13 or older but under the age of 18, you should review this Agreement with your parent or guardian to make sure that you and your parent or guardian understand it. Additional age restrictions apply for products containing objectionable material.
As a registered user of the iTunes Service, you may establish an account ("Account"). Don't reveal your Account information to anyone else.
In order to purchase and download iTunes Products from the iTunes Services, you must enter your Apple ID and password or use Touch ID to authenticate your Account for purchases. Once you have authenticated your Account using your Apple ID and password, you will not need to authenticate again for fifteen minutes on your computer or iOS Device; you can choose to allow your computer or Apple TV to remember your password to remain authenticated. During this time, you will be able to purchase and download iTunes Products without re-entering your password. You can turn off the ability to make iTunes Product purchases or change settings to require a password for every transaction by adjusting the settings on your computer, iOS Device, or Apple TV. For more information, please see
http://support.apple.com/kb/HT1904 and
http://support.apple.com/kb/HT4213.