No, they admit people without a BS in CS but I think they want to make sure you'll be able to succeed in the program. So it helps to have professional software engineering experience or some other coursework.
> however, work experience will not take the place of an undergraduate degree.
You can get it with a non-CS degree + work experience (see sibling threads).
Some schools accept master's students without an undergrad degree at all but AFAIK most don't. This program doesn't.
I haven't met anyone in the program with an econ degree. Mostly CS, and engineering. And a few with physics or math degrees.