The App Store is a developer's best friend, until your app is rejected. (Are you suffering from App Store Rejection? You aren't alone - watch this humorous video.)
App Store Guidelines
"We will reject Apps for any content or behavior that we believe is over the line. What line, you ask? Well, as a Supreme Court Justice once said, “I’ll know it when I see it”. And we think that you will also know it when you cross it."