I have seen a couple of situations were a course have appeared in a couple of diffrent programs assigned to the same user (though not offten).

Tracking a users route I would suspect is hard once the user has accessed the course once and completion tracking started, the course could be accessed from many different places outside of the program it's self. 

A block should be easy to do, show all the programs the course belongs to that the user is also enrolled on.... I think it's of benefit to show the user all the programs as, I would want to see what progress I achieve by completing this 1 course... and that may be progress in serveral programs.