I'll admit that this question stems more from indirect experiences through popular culture and not real-life experience (fortunately), but I think there's still some real-life backing to it.
The "Miranda rights", as established in Miranda v. Arizona, must be read to a subject prior to interrogation so he or she is aware of the possible consequences of statements/confessions/etc. However, typical depictions of arrests - at least in popular media - show suspects being "read their rights" during their arrest, despite the fact that they are not undergoing, nor immediately about to undergo, any form of interrogation.
Why is the Miranda warning typically depicted as being given during an arrest, and not immediately before an interrogation? Is there a law that states that this is necessary?