For highly motivated students there is a choice you can learn more or keep a higher GPA. This split often starts around 3.0 GPA and becomes most obvious when someone try's to keep a 4.0. In many ways this is why Harvard and MIT students are so prone to cheating, try keeping a 4.0GPA and do interesting things on the side without cutting some corners somewhere.

PS: Try running the numbers some time; there is a lot more openings in top collages than there are geniuses in this country. So most of people at “top” schools not all that more intelligent than the average person.