You absolutely have to monitor summon — there are just as many stories about Summon hitting things too.
You can monitor Summon from outside your car and interrupt it (by app I guess on the M3, on the S/X by keyfob press) if it looks like it’s going south. You can do so by standing either in front of or behind the car and watching how it’s doing.
The argument in favor of Summon is that some people suck at parking situational awareness and do a better job of monitoring from outside the car than inside. You can decide for yourself if you subscribe to that view.
With that said, where this becomes dicey is the “allow tight spaces” equivalent option. By default Summon won’t allow getting closer than 4 inches or so from an obstacle. This option takes it down to like 1 inch.
Summon moves at 1mph. If you can’t interrupt a car moving at 1mph heading towards trouble, it really sounds like you’re not paying attention. But when you take that margin down to an inch, it’s risky. Things can go south really quickly.