Back in the early '80s when I had a summer gig working at a fishing lodge in northern Manitoba, and not enough flying hours to get a real job, I would routinely talk my way into the cockpit (often the the left seat) of Perimeter Metros and, occasionally Air Manitoba Daks. (YWG-YGO) There wasn't a functional cockpit door, the passengers couldn't have cared less, the FO got a charge out of being in charge, and had the opportunity to teach me whatever he was inclined to, and the Captain got a nap back in the cabin.