I was just watching the movie tonight and it hit me. Why didn't anybody think something was up with the fact there was no paperwork on Bumblebee. If I were Sam's dad and had just paid $4,000 for a car, I'd want to fill out all the necessary title transfer paperwork. Since Bumblebee was not a real car or even on Bobby B's lot, he wouldn't have had any. Therefore Sam couldn't get tags or anything else. Why didn't this throw up a red flag?