Brian and Rowan own adjoining cottage properties on a lake. While both properties have lake frontage, only Brians is capable of having a dock. Brian agrees to let Rowan use his dock for his boat and to create a path from Rowans property to the dock. Being cautious, Rowan has this agreement written down and signed by both of them. Five years later, Brian sells his cottage to John, who immediately blocks off the path and tells Rowan to get his boat off Johns dock. Rowan mentions the written agreement with Brian and says he will sue to enforce it, but John says he is not bound by any agreement signed by Brian. What is the main legal issue? Is John correct?