I don't think that's what they mean. If you are in NYC then yeah if you don't visit they'll really wonder why, but if you're not from the tri-state area I think they understand that not everyone can for a variety of reasons. There are other ways to learn about a school without visiting like going to an info session in your area or reaching out to students or alumni to learn more about the program. I think that Stern asks that question because they don't want to get a lot of applications from people who are using it as a back up to Columbia and don't take the time to learn about Stern. So the best answer to this question, IMHO, would be more about demonstrating how YOU fit in with Stern and using your observations of the school's culture and offerings as evidence. How those observations are made will be different for different people.
I was reading the Berkeley essays and they have a very similar questions:
"If you have visited Haas, please let us know what about your visit made the most lasting impression on you. If you have not visited Haas, what steps have you taken to familiarize yourself with our MBA program?"
I guess they are used as backup for Stanford....so its important to show that you are not considering them as backup (both for haas and stern).
I believe its yogurt!