maybe you can do this to hide the BCC part in the ticket post
in include/staff/viewticket.inc.php:
Find:
To:<input type="text" name="send_to" value="<?=$ticket->getEmail()?>">
CC: <input type="text" name="cc_to" >
BCC: <input type="text" name="bcc_to" >
And replace it with:
To:<input type="text" name="send_to" value="<?=$ticket->getEmail()?>">
CC: <input type="text" name="cc_to" >
<? if($thisuser->isAdmin()) { ?>
BCC: <input type="text" name="bcc_to" >
<?}?>
i think thats the solution you need.
Maybe you can post the BCC part in note comments.