Amy B: You applied to Marshall? I applied there as well. Did you interview there yet?
To answer your question, most schools know that you are applying to both MD and DO schools. Questions like this are sometimes asked to "pressure you" to see how you react. I applied to Marshall U, WVU, and Louisville, along with PCSOM, VCOM, and WVSOM. Every place I interviewed asked me if I applied to the alternative school. DO schools will ask this question also to see if you understand the DO philosophy.
I was asked by a couple schools were I would go if I was accepted to other schools.
I agree with Amy B's response. The reasons that I gave for choosing osteopathy was that its principles and philosophy were in proximity with my own philosophy. I currently work in a hospital in Huntington, so I used my experiences working in Cardiac Rehablilitation as well. But honestly, schools wont decline to interview you based solely on whether you applied to both DO and MD school. Good luck with your interviews.