Depends who you go with. It's true that some people just go to hang around with friends, but don't pay those people any mind. Me and my friends attended nearly every lecture, taking breaks to eat or pray, from morning until night, and I came back from that event with much more knowledge than I ever would've gained here, alone, during the semester-where time is already lacking.
Definetely try to go, you won't regret it

It takes place in Toronto, but it's worth the trip if you live in another city. Are you familiar with the MSA? If so, you can check with them, chances are they organize an annual trip there for anyone who wishes to go.
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Do you mean the seating area will be segregated or the entire room?
MashAllah 22000 people huh..? I heard the announcers say that it was three time more than last year, but we never got a definite number, MashAllah! Hopefully you guys will have as much success.