The author of AirFloat on its App Store removal:
I realized that this would never make it to the App Store. Even though it would be 100% within the App Store Guidelines – given this was a reimplementation – Apple posible wouldn’t approve it due to the usage of the AirPort Express’ private key.
But then something remarkable happened. Apple approved Air Speakers – an app that enabled you to stream audio to your iOS device from iTunes and iOS devices. Using the private key of the AirPort Express.
But after all, they still got removed. The official statement is that it’s due the use of Private APIs, yet I don’t buy that: imho it’s due the use of the private key which the Airport Express uses to decrypt the audio streams it receives.
Although I’m not surprised with this removal (of course Apple won’t allow it, as they’ll eventually lose money if they wer to allow it!), it once again is a fine example of why the Apple app approval system sucks: at any given time Apple can decide to sack your app because they don’t like something in it. The App Store Review Guidelines explicitly leave wiggle room for Apple:
This is a living document, and new apps presenting new questions may result in new rules at any time. Perhaps your app will trigger this.
Roughly translated: bend over.