What are you trying to accomplish by drawing these lines? An interactivity map?
Miguel Angel Wong commented
It seems by the attached image the user is requesting an additional option to generate a less-cluttered navigation map.
I'd like to see this too, but with the option to be able to print those lines.
I would use these lines to get a quick overview over the main ways a user can go. (Or the main overview of the flow of a certain section.)
Using the prototype mode as is, showing all links, gets cluttered and gives me no such overview information.
Keep on making XD awesome!