40caljustice, I'm not a lawyer, let's get that out of the way early. I'm reaching back to an undergrad criminal law course from a couple decades ago, and various reading on the subject.
Look up "excited utterances."
Note CaptCharlie's point about letting guys stew in the car; no questions have been asked; no questions are being asked. If the suspect chooses to blurt something out, his lawyer may have a lot of trouble getting any such statement thrown out.
Those are just two examples where Miranda may not be determined to apply. I'm sure there are others, but again, I am not an attorney.