I can't imagine a set of regulations that would be reasonable. I have friends who have completed all the levels of Candy Crush Saga without spending any money,

I can't imagine a set of regulations that would be reasonable. I have friends who have completed all the levels of Candy Crush Saga without spending any money, yet it's probably the most successful example of this ever. According to the article 80% never paid. For the example you cite I completely agree, taking a casino game and making it IAP is horrible and should be regulated like that. However you word that though, you're going to have horrible developers find a way around it. Anything short of banning IAPs is going to be worked around, and banning IAPs doesn't sound like a reasonable idea. The other thing is 18+ as regulation, I'd be staggered if that was pulled off successfully. Lots of things on the internet are 18+ and not used exclusively by adults. That's an unworkable regulation by any precedent. This is really horrible, but I don't see any way to regulate it successfully.