I was under the impression you needed to enter your app store password to make a digital purchase.

The vulnerability i thought was that the iPad remembered the password for a short amount of time, if you handed your iPad to a kid in that time they could fire up the app and make a purchase without needing to re-enter the password. Typically though, the kid would be unable to make purchases without a password.

I lesson I learned quickly on the iPad was that few applications were really free. Either the ad's were intrusive or the majority of the content had to be purchased. I typically do not bother with free app's any more and just look for a high rated paid version.