title: When to make a type non-movable in C++11?
body: <p>I was surprised this didn't show up in my search results, I thought someone would've asked this before, given the usefulness of move semantics in C++11:</p>
  <h3>When do I have to (or is it a good idea for me to) make a class non-movable in C++11?</h3>
  <p>(Reasons <em>other</em> than compatibility issues with existing code, that is.)</p>