no, not 'u', but maybe [[:cntrl:]]?

Hm... I'd really like to reproduce this! Could you check what this script outputs (was "Алек©ей" the user name that triggered the error?)?

<?php
function matches($string)
 {
  if(preg_match("/([[:cntrl:]])/", $string)) return true; // control characters
  return false;
 }
 
if(matches('Алек©ей')) echo 'matches!';
else echo 'doesn\'t match!';
?>

I get "doesn't match!".

Alex