title: Is there a downside to session.auto_start in PHP?
body: <p>I usually end up adding <code>session_start()</code> to the top of every page on my PHP sites (or in a header file which is in turn included on every page). I recently discovered that you can have sessions start automatically by using the following setting in <code>php.ini</code>:</p>
  
  <p><code>session.auto_start = 1</code></p>
  
  <p>What are the potential downsides (if any) of using this setting?</p>