title: When are you truly forced to use UUID as part of the design?
body: <p>I don't really see the point of <a href="http://en.wikipedia.org/wiki/UUID" rel="noreferrer">UUID</a>.  I know the probability of a collision is <em>effectively nil</em>, but <em>effectively nil</em> is not even close to impossible.</p>
  
  <p>Can somebody give an example where you have no choice but to use UUID?  From all the uses I've seen, I can see an alternative design without UUID.  Sure the design might be slightly more complicated, but at least it doesn't have a non-zero probability of failure.</p>
  
  <p>UUID smells like global variables to me.  There are many ways global variables make for simpler design, but its just lazy design.</p>