What happened here can be analogous to scenarios such as the following:
* toaster instantly carbonizes toast
* tapping the accelerator causes it to stick, accelerating against the brakes
If a car has a functionality such as 'autopark' (or 'summon', which suggests the user would be able to do it without being in the vehicle), it should not matter whether the person is in the car or not. It should do the right thing, every time, with complete obstacle avoidance - not just when there's no curb or wall in the way.
The exact same thing could happen in the same scenario, taken from the 'official' ad video found on Tesla's site, here:
1) Wife goes shopping in her Tesla
2) Husband comes back from shopping with a new canoe, secures to back of garage with hooks suspended from the ceiling
3) Wife comes home, parks in driveway, goes inside
4) Wife uses summon mode to park vehicle
5) New canoe is now implanted in the windshield of vehicle.
Regardless of whether the user accidentally or intentionally activated the mode, the mode performed improperly, resulting in vehicle damage.