One particularly egregious example of Miranda error is in Frasier, when ex-cop Martin says:
One time when I was on the force, I saw a guy shoot somebody. When we caught him, I started to read him his rights, but he slipped out of his cuffs and he swung at me, so I didn’t get a chance to finish. Two months later, I’m on the stand and his lawyer asks me if I read him his rights in full. Now, if I say no, this guy walks, and this guy has been in and out of jail all his life. He could have read ME his rights. So I say “Yes, I did. I read 'em in full.” I lied under oath. Now, you might think that I did an unethical thing, but there’s not a doubt in my mind that I did the right thing.
So what if any defendant statement is excluded? You have eyewitness testimony - and that will be sufficient
Not only that, Martin was arresting him not questioning him. His rights would have been read before someone started questioning him. But at that point no one would care if he made a statement or not since he shot someone in front of a cop.
In over 25 years as a cop I never once Mirandized anyone when I arrested them. As a patrol cop I rarely had to Mirandize anyone because it wasn’t my job to interview them. Any spontaneous utterances that were said were noted. I knew if I asked specifically about the case it would be thrown out anyway. As a detective I often Mirandized people and either had them sign a form or waive their rights on camera (or both) before questioning. It’s never required at arrest.