My dad bought a pre-owned 1969 Continental Mark III, literally in the dark. He went to see it at night and bought it on the spot. Don't ask me what he was thinking, but he clearly wanted a Mark III badly. It was the classic color combo from the the full width magazine ads: burgundy with a black vinyl top. When he got it home, I immediately noticed it had a Thunderbird emblem on the steering wheel. It also had eliminator pipes that did away with two of the four mufflers, and had wheel covers off of a '70 or '71 model, which were entirely different looking from the '69 covers. One day we were out in the car and spotted a Mark IV on a small used car lot nearby. It had '69 Mark III wheel covers, which looked hideous on it, so we stopped and proposed a trade. The dealer didn't hesitate to make the switch on the spot.
That Mark III drove beautifully and rode like a cloud, but it was otherwise sketchy. Once when it was parked on the driveway, which was fairly long, my dad started it and while it was sitting there running at a fast idle from the cold start, it popped out of Park and into reverse (automatically releasing the parking brake), backed down the driveway at a pretty good clip, started heading into an arc and barely missed the front of the house, proceeded across the front lawn and if not for a young Mulberry tree in the parking strip, which it hit with a loud cracking sound (the tree survived with a scar that remained for a several years), the car would have headed into the street to raise havoc and likely trigger some serious insurance claims by the neighbors.
There was no visible bumper damage. My dad was working out of town frequently at that time, and he instructed me to sell the car. Some guy came along and I got him to pay more than my dad did for the car. Apparently he wanted a Mark III really badly too. I wonder when, where and how that cycle finally ended.