If a an interviewer thinks, "Hm, this person is applying to very different schools, he must be an idiot," then that interviewer is dumb for drawing such a conclusion.
For instance if someone applies to Wharton and Fuqua, they're considering two very different schools, one is very quantitative and very competitive (in terms of how the students interact), while the other is less quantitative and more collaborative. But there may be very specific things about each school that appeals to the person, and it's totally valid for them to apply to both schools.
I guess to answer your question, I'm sure if you told an ad-com that you were applying to INSEAD as well as Haas they would probably think, "That doesn't make sense," so it's best not to tell them where you're applying unless they ask in such a way that there is no subtle way to avoid the question.
Only each individual applicant understands the pro's and con's of the different schools that they're applying to. As many of us don't know exactly what we want to do after school, it's totall legitimate to pick schools that are very different.