[@BytheSpleen] to be honest Ms. Shiba is still holding the sign and does not have the roster on her. If she did it would have been the entire roster of students at the academy and that would be impossible to see specific ones. Also the fact that Hisoka doesnt know all of the new students names so even if he could see the roster he wouldn't know who is who only Emi. The rosters at a magic knight school would not hold pictures of the students due to assassins and grudge holders(who have forgotten faces of course) would break in and try to kill said student.