Karen and Gerald Baldwin owned property in Rapid City, South Dakota, which they leased to Wyoming Alaska Corp. (WACO) for use as a gas station and convenience store. The lease obligated the Baldwins to make repairs, but WACO was authorized to make necessary repairs. After seventeen years, the property was run-down. The store’s customers were tripping over chunks of concrete in the parking lot. An underground gasoline storage tank was leaking. The store’s manager hired Duffield Construction, Inc., to install a new tank and make other repairs. The Baldwins saw the new tank sitting on the property before the work began. When WACO paid only a small portion of the cost, Duffield filed a mechanic’s lien and asked a South Dakota state court to foreclose on the property. The Baldwins disputed the lien, arguing that they had not requested the work. What is the purpose of a mechanic’s lien? Should property owners who do not contract for improvements be liable for the cost under such a lien? How might property owners protect themselves against a lien for work that they do not request? Explain.