i>Now programmer (3) comes along and make his change. The behavior of the 
  original (and distant module) remains unchanged because the 
  <code style="white-space: normal">construct_from</code> trait has been set to 
  "track_never" so he should always get copies and the log should be what we expect.
  <p>
  <li>But now he gets another trap - trying to save an object of a 
  class marked "track_never" through a pointer. So he goes back to 
  construct_from.hpp and comments out the 
  <code style="white-sp