That's right, the ultrasonic sensors can't detect every single overhead obstacle. If you can imagine "a cone of visibility" from each sensor, there are always going to be "blind spots". Same holds true for the side doors. The sensors are on the FWD and if there is a thin pole centred on the front door, the car won't see it either.I tried parking my Model X in my extremely tight garage and opening up the falcon doors with the garage door opener hanging down towards the front part of the car. The car was already off at the time. I was curious if the doors would sense the garage door opener box hanging from the ceiling, but unfortunately it did not and the top driver-side glass was pierced and had get to get it replaced. I am guessing that this is a weak point for the X? It's not able to always "see" a single object hanging down from the ceiling vs. the actual height of the ceiling?