Too many In-App Purchases traps

The more I use apps these days, the more I realized that many apps (particularly games) use In-App Purchase as their main source of income.  However, because of the nature of games, it's pretty to distinguish whether you are dealing with virtual money (currency used in game just for fun) or dealing with real world money (those that charge your credit card directly).  So to me it's pretty important to to turn OFF in-app purchase feature so that at least the iOS will prompt me a message telling you when you are suddenly dealing with real world money.

To turns off "In-App Purchase", simply go to setting [General][Restrictions], and set "In-App Purchase" to off.