If you approach too many girls on campus and get rejected you will get known as "that guy" and the "creepy guy" I've had that happen it's not fun. It's not socially calibrated to hit on girls aggressively during the day. It's calibrated to do it at parties. And if you say you'll wait for IOIs... well thats pussy game and you will probably get nowhere with it.
That's an accurate assessment. Cold approaches are pretty much the fasted way to social exclusion. Even at a big uni, you'll realise that the upper echelons all seem to know each other somehow. The social model is rather simple in theory and practice. Find a cool popular guy and befriend him (this could also work with a female provided that she's more an average social butterfly than superhot vixen). You hang out with him in between class and you'll be introduced to all the cool kids. As long as you stay fit, aren't hideous, are well dressed and aren't socially retarded you'll soon have a decent circle of people. You've got to sell yourself indirectly abit though (cool style etc).