I usually like this feature, for example when I'm carrying a box full of booze, but I recently had an issue that nearly cost me a fortune. I had the lift gate open, and the stupid thing sensed me standing behind the bumper, I never waived anything under the vehicle. It started opening and pinned the lift gate against my garage door. If I hadn't forced it to stop, it would have likely broken the damn lift gate glass.
How dumb, having the lift gate open should disable the motion tailgate unless you physically push the button to open the tailgate. I've found several of these dumb things, makes you wonder if anyone actually tests things like they might get used in the real world.