True true, but this was meant to be a whimscial/goldbergian solution. You'd have to be wary of the same issue with /e though not /ge ;-) Of course this fixes that:

$i = 0;
@no = qw(one two three four five);
foreach ( @no ){
  my $str = '';
  while( s/([^e]*)e// ){
    $str .= $1 . "fee" . $i++;
  }
  $_ = $str . $_; #UPDATED: Append addresses Re: to this node
}
print "@no\n";
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--
perl -pe "s/\b;([st])/'\1/mg"