improbable, yes. Impossible? no.
two layers of insurance is better than one when the cost of that second insurance is simply pulling up or pushing something with your foot.
Also, just as another piece of information, my aunt has a suburban that has been parked on a hill nearly every day for almost a decade, and she rarely ever uses her parking brake. In just a few years, the gear shifter had begun to be harder and harder to take out of park with the weight of the vehicle being placed on the pawl/gear instead of the brakes. Now, anytime she tries to take the vehicle out of park when the weight in on those parts instead of the brake, there is a loud thud as the pawl is disengaged and a jerk of the vehicle. I'm sure there is a gouge in either the pawl or the gear that has been worn into one, or both of them as a result of that weight being applied on a daily basis.