I think at that point they expect you're done with the camera. You can always turn it on again while parked.
As suggested, use the parking brake. Just shifting to park engages the parking brake pawl inside the drive housing and there is quite a bit of play in there. Applying the parking brakes holds it with the rears quite well.
I don't think they could make trailering any easier.
Ford engineers are wrong if they think that people can line up a trailer hitch on first try, every attempt and then just put their truck into park.
Even those experienced at the task sometimes take two or three attempts. Even with the camera.
