I learned that the hard way!
I was behind the truck washing my floor mats with the key on Acc., listening to the radio. My two year old son had climbed in the font "passenger" side. You can probably guess the rest of the story.
With little effort, he put it in reverse. The driveway had a slight slope towards me. I had my back to the truck about ten feet away, kneeling.
Needless to say the truck hit me pretty hard. Fortunately, since I was facing away from the truck, the force knocked me a few steps forward, allowing me to get to my feet. I was able to get out the way and begin pursuit. The vacuum was being drug under the truck.
Thank goodness he didn't lock the doors. I was able to catch up, hop in and stop it before it really got going down the hill.
I never would have thought the truck would go in gear without the motor running.
Though I wasn't the last person to drive the truck, I took full blame for that one....ASSuming the Parking brake was set, and not checking.
Hopefully this little life lesson keeps one you guys from getting run over in the future.