OK I would like to clear this up once and for all because this is starting to piss me off.
Based on my experience, No it is not as chill for the applicants as you are trying to portray it. And NO this question is NOT "innocently" asked by the great majority of interviewers. It is usually asked by people who feel insecure about their program and are worried that they won't be ranked high enough and won't fill. If an applicant discloses how competitive he/she is, most likely it will affect him negatively.
Now let me make this clear:
IT IS AN NRMP VIOLATION TO ASK THIS QUESTION !!!!
This is copied directly from the NRMP's document entitled
Professionalism and The Match: Important Considerations
Under:
Consequences of Engaging in Unprofessional Behavior Failure to comply with all the terms and conditions of the Agreement, whether intentionally or not,
may result in an investigation and the imposition of penalties.the violations most commonly reported to the NRMP include:
"..... 2. A program director asks an applicant where else the applicant has applied or interviewed. Although applicants may volunteer information about their other applications and interviews,
it is a violation of the Agreement if a program director requests that information. Similarly, applicants and program directors may volunteer how they intend to rank each other, but it is a violation of the Agreement for either party to request that information .... "
This is the link to the full document
http://www.nrmp.org/wp-content/uploads/2013/08/Policies.Statement-on-Professionalism.docx.pdf
I honestly feel that my rights as an applicant are violated when I'm asked this question, and honestly I would encourage reporting violations because this F'ed up practice needs to end. It still occurs because they are getting away with it. It is none of their business where we are interviewing, they already have the upper hand in the interview but they want more control by asking this question.