I noticed it is possible for an iOS app to continue recording audio in the background while another app is in the foreground recording audio (note that this isn’t strait forward on the iOS simulator, but a hack involving a background process makes it possible).
Is there any way to ensure that no other apps are recording audio before you start to record? If so, is there any way to stop other recording apps so that an app can record?
No, you cannot hinder another applications functions (well not using the iOS SDK) the only way this would be possible is on a jailbroken iPhone. But with an application built for the App Store this is not possible.