The Federal Trade Commission (FTC) has said they will be investigating in-app purchases for applications marketed to children, such as Smurfs' Village. The argument is that some children do not understand the difference between real and virtual purchases.
In a letter to Rep. Ed Markey (D-Mass.), FTC Chairman Jon Leibowitz wrote:
We fully share your concern that consumers, particularly children, are unlikely to understand the ramifications of these types of purchases. Let me assure you we will look closely at the current industry practice with respect to the marketing and delivery of these types of applications.