It is really no surprise that some students, mainly from wealthier public and private schools, are better prepared than some of their peers. That doens't mean, however, that they do not fall into the same habits as the rest of us.
Professors across the country have been complaining as of late that students are unprepared for their classes. This comes as no surprise to most of us. Yes, we learned theorems and concepts in high school, but we also learned how to coast through assignmets and write puff pieces that were "just good enough.."
With that said, whether or not homework is completed is entirely up to the student. It should not be forgotten that college involves more dimensions than the high school life. In addition to classes you have the option of fraternities, clubs, internships, and exploring the city in which you study.
Classes are important, but so are the opportunities and responsibilities you will pick up on the side. These (hopefully) four years are your launching pad into the real world, and balancing work and fun is one more thing we all have to learn.