Well, I think it really comes down to how much you really care about getting accepted to ICO. Did you get acceptances elsewhere? If so, and you are satisfied with the school(s) you were accepted to, I probably wouldn't bother because I know it is very costly to go to these interviews.
I'm from CA and I spent about $1500 (plane ticket, hotels, shopping, other costs) going to NYC and Chicago for my school interviews. I thought it would be a complete waste of money if I simply went for there for the interviews, so I stayed 1 week at both cities and had a blast. This way, I knew I wouldn't feel bad if I didn't get in to the school or not.
I thought I had wanted to stay in CA for school, but seeing the school facilities, meeting the professors, students, and getting the feel for the environment really changed my perspective on where I wanted to pursue my education. Although I got into a school in CA, I'm choosing to go to ICO now.
So think about it. If you've never been to Chicago, then why not treat yourself to a mini-vacation?