Most people in my lectures use laptops for Fb, etc and don't make many notes. The rest have genuine reasons like dysphraxia (no idea how to spell that) or unintelligible handwriting.
Seminars are a must, and nearly always registered but lectures aren't always registered, it depends on the uni and course. I'd advise you don't take laptops to seminars (often it's in a small room and you'll take up a lot of space with something unnecessary anyway. I wouldn't take laptops to lectures either. Mainly because a lot of people don't have insurance that covers their stuff when it isn't in their room so if it is lost / broken / stolen then tough ****. But also because it's easier to just take notes the old-fashioned way, and because you don't get distracted so much. You'll have enough free time that you will be able to go on Fb after your lecture and like your friends photos or untag ugly pictures. But Craig_D kinda answered the question as best as could be done. So there isn't much else to say...