Yesterday, I picked up my 550 at my dealer. After settling the bill, I went to the car and started it. The car was cold. I realize I needed to go to the bathroom and figured the engine would warm up while I was gone. Of course, the mechanic who drove the car to the customer parking lot put the parking brake on. No problem. I left the car with the engine running and went to the dealers restroom. When I came out, I saw my car slowly rolling toward the curb. Yipes! I ran to it and tried to stop it. Say, this car is not a lightweight. The owner of the dealership was walking by and helped me. We did stop it. Now am I stupid or what?