A few years ago, I was looking into buying a Jeep Grand Cherokee. In my research, I found that there were some disturbing reports that it had a history of "falling" into gear and accelerating all by itself while left in park. Obviously, this wasn't a regular occurance, but apparently it happened in Grand Cherokees far more than in other vehicles. I guess most times, the vehicle would just hit the wall in front of it or the vehicle in front of it without having had time to accelerate to a dangerous speed.
Though you'd like to think that if there was someone in the car when this happened, they'd be quick enough to hit the brake!
The reports were enough to convince me to pass on the Jeep.