<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by The Unknown Screener:
No there is no such rule. If it is done in the lobby and in plain sight you most certainly can watch. I used to ask passengers if they would like to watch, most said no and walked to the gates.</font>
EWR (terminal C at least) has big partition things up to prevent people from watching what is going on. They tell you that you can't see what they are doing for "security reasons."