The chase scene in Trancers(1985).
Toward the end (right after Thomerson and Hunt leave with the homeless man, after being shot at), they're avoiding the cops on their tail, and you can clearly see the microphone at the top of the screen at one point, per se.
That was a great goof in Eddie & The Cruisers. When two of the guys are talking backstage after one of them had been performing, a boom mic drops into frame for a few seconds. I love when those mistakes happen.