This caused the app to get rejected. I wanted to blog this, because I've read in several places on the internet that this method is NOT a private API and wouldn't get your app rejected. I've also heard rumblings that Apple is now using a static analysis tool to detect private API usage, so maybe that is why it was rejected.
Anyway, I'd stay away from this API if you want your app approved, and if you've already got an app on the App Store with this API, you might be careful submitting updates to it. We ended up removing the slider altogether, as it wasn't really needed.