Not sure why you think that. The ADOT statement is a warning to a potential buyer of the vehicle that there is at least one lien against it. Such has nothing to do with placing a junior lien on the vehicle - no different than placing a 2nd mortgage on your home.
Then I suggest that you stop trying to "help" these folks and let their attorney advise them. While I could be wrong, I doubt very much that this type of a "loan" is a typical title or registration loan as I doubt lenders like Speedy Cash or Title Max would loan $100k.
Des.