It's not just about you though. In a lecture of 100+ people on laptops, you're bound to have plenty of distracting people browsing youtube, watching flashy vide

It's not just about you though. In a lecture of 100+ people on laptops, you're bound to have plenty of distracting people browsing youtube, watching flashy videos or somesuch. That sort of thing can affect the people around you negatively. In that regard, it's hardly any different than asking the hall to be silent while the lecture is on, rather than everyone chatting out loud.