Sorry, but that “theory” makes no sense at all if you were actually familiar with Chappaquiddick Island — there was no place for them to be “parked” between the party house and the fatal bridge, and there was no way to drive the car “into town” at that hour of the night (the tiny ferry had ceased operation for the day). The only plausible reason that car was being driven at that hour was to go the isolated beach beyond the bridge. We can’t “prove” it but if you read up on the case it is clear that Teddy was driving her to the isolated beach for his hanky-panky. All the “wrong turn” b.s. that he put out was just that, b.s. And the idea that he was not driving the car makes no sense when he acknowledged he was driving the car (which he tried to avoid having to say and which he never would have said if he’d felt he had any other option).
I think he was on the way to the beach for hanky panky until they passed Officer Look. They “sped” off. I think Kennedy got out of the car, and told her to drive to the ferry, that he’d meet her there, or maybe he walked down to the beach to meet her there. He was drunk on his butt. He probably passed out, then swam back to the motel.
He probably blacked out, and had no recollection at all about anything until he two buddies confronted him at the motel the next morning.
No way, no how he was in that car. If she couldn’t get out, how did he?