Heard rattling in the door and found these under the car.

[macr6]

I just bought a 2017 S5 in September. Was driving down the road with the windows up and the radio off (just enjoying the engine sound), and heard this rattling noise. I noticed that it wasn't when I was hitting bumps but just randomly. Sounded like something was in the door. After a couple weeks of going crazy I made an appointment with the dealer to find it. Two days before the appointment I'm walking to my car in the parking garage and see these two white loops under the car. Bend down to check them out and they slide back and forth. So I found the source, but can anyone identify what they are? I'm sure it has something to do with delivery.

[Crucible35]

Those are the hooks that secure the transport cover to the car. I experienced the same thing you did when I picked up my last Audi....little over a year ago. Basically, our dealerships did a crappy prep on our cars. Rather than unhook the white sheet, they tore it off....leaving the hooks. I heard them, then looked underneath to find three of them. They rattled some more so went back under and found three more! You may want to check underneath all around your car.....you may find a few more.