Private APIs and Why Apple Bans Them (cocoacoding.com)

I just wrote this article about Private API use and Why Apple is so strict on enforcing it. Although some might say this topic is old, I recently found myself getting an app rejected for it. I had been searching on Stack Overflow for a quick way to insert a textField into a UIAlertView and found an user posted answer which used an unofficial way to include one. Months later, Apple rejected my application because it used this undocumented code.

My question to other iOS Devs, have you ever been caught using code which is deemed undocumented?