title: How unique is uniqid?
body: <p>This question isn't really a problem looking for a solution, it's more just a matter of simple curiosity.  The PHP uniqid function has a more entropy flag, to make the output "more unique".  This got me wondering, just how likely is it for this function to produce the same result more than once when more_entropy is true, versus when it isn't.  In other words, how unique is uniqid when more_entropy is enabled, versus when it is disabled?  Are there any drawbacks to having more_entropy enabled all the time?  </p>