What happens if Apple detects hidden API usage in an iPhone app?

Question

Would they just take the app off from the store / not let it pass in, or would the cancel the whole contract with the developer?

Answer 1

In theory, it wouldn't even be accepted in the first place, even if they're wrong when they think you do use them:

http://landonf.bikemonkey.org/code/iphone/Apple_Lesson_Huh.20081213.html

But there seems (or seemed) to be some exceptions:

http://landonf.bikemonkey.org/code/iphone/iPhone_Private_API.20081206.html

Answer 2

In practice, Apple does not really scan for this but if they detect it they'll simply not accept the app and ask you change it.

Every once in a great while Apple will pull an app they find breaks some of the rules, but that's pretty rare.

The main risk is your app will break in an update.