There is one way this can legally happen.....
Customer drops off RV in October, Repairs are done and the customer is called, but decides to leave it at the dealer for the winter, free storage he thinks. Well time passes, November, December, January, eventually, since the bill has not yet been paid (Customer plans on paying when he picks up) a Garage Keeper's Lean is filed, and after the proper paper work, and notices are sent, the trailer is sold to pay off the lein.
But I am guessing that is not the story here.. Still, key word, Guessing.