I predict that this will be an unpopular opinion (and I know that you weren't taking sides when you posted) but as ****ty as yield protection is for peers/fellow applicants, I don't necessarily blame those that hold on to a few extra invites and end up going on a few interviews they otherwise wouldn't have in a normal year due to having more time and decreased travel costs. Assuming that the applicant "earned" the interview, he/she shouldn't feel bad about turning down an interview, just so that it could go to someone else, if there's even an inkling that he/she could see themselves ending up at the program.
Yes, I agree that purposeless interviews should be avoided. But say an applicant goes on 20 interviews and ranks all 20 places, I don't think he/she should be penalized in that scenario. On the contrary, the applicant that goes on 25 interviews and ranks 10 is the a$$hole, IMO.
I think it should be up to the programs to either be interviewing more people this year--and ultimately expand their rank lists--or for the AAMC/NRMP (whomever wields that power) to have capped interview numbers. The latter is water under the bridge, the former is not.
TL;DR hate the game (the system as it currently operates), not the player (the applicant that might want to check out a few more places on his/her list).
Edit: I'm just tired of med students placing blame on peers, when in reality, the blame should be directed toward those in positions of power.