title: Are user names ever case sensitive?
body: <p>I'm looking at some code that converts user names to lower case, before storing them. I'm 90% sure this is ok, but are there systems out there that actually require case sensitivity on the user names (specifically in the health industry)?</p>
  
  <p><strong>Note:</strong> my particular code is not at the point of entry.  We are taking user names from other systems.  The worry I have is depending on those systems (which may or may not be under our control) to consistently pass us usernames in the same case as each other (when describing the same user).</p>
  
  <p>Also of note - the code is:</p>
  
  <pre><code>userName.toLowerCase(Locale.ENGLISH)
  </code></pre>
  
  <p>Are all user names in english?  Is this just so it matches collation in the database? Note that (in java at least) <code>String.toLowerCase()</code> is defined as <code>String.toLowerCase(Locale.getDefault())</code></p>