IMO this would be a terrible idea to let the robots park cars in the same car park as humans. They most likely have a dedicated car park for this where ever car is parked by a robot.
The article says:
"A Stanley Robotics autonomous parking robot then slides underneath the vehicle, lifts it by its tyres and transports it to a secure storage area."
Which seems to suggest this.
It sounds like the actual lot will be robots only as it mentions parking cars closer together to maximize capacity.
I think the OP was talking about humans parking weirdly in the garage the robot picks them up from, not the car park itself—the car park itself is robot only (so they can jam cars together).
The parent is wondering about parking in the bay, before the robot picks it up.
Robot = some 3rd world country guy driving in remotely