While I whole-heartedly agree that holding onto interviews that you knowingly can't or won't be attending is unprofessional, selfish and just mean to your fellow med students and while I personally would love to have a few of those interviews myself (it's been a tough year eh?), I have a really hard time believing PDs are spending the time and effort to contact, coordinate and identify applicants that are holding interviews to different programs for the same day. I think these orthopaedic surgeons are extremely busy with their own professional and personal lives to do something like this.
It makes a little more sense for a program to seek out and blacklist an applicant if he or she confirmed an interview and then never showed up or if the cancellation was a day or two before the interview (as this is extremely unprofessional), but for PDs (or even program coordinators) to contact every other PD and send out lists of applicants with confirmed interview dates? That seems unlikely.
I think it is both beneficial to you (as pointed out in the previous post) AND better for orthopaedic surgery residencies as a whole to give a solid 2 week advance notice in cancelling interviews (and be aware of the holidays for that first week of january). However, this has already been stated and we have been reminded multiple times in many different threads to do this and I personally feel that any fear-mongering or rumor starting is beneath us.
But hey, who knows, maybe this really is true.