Ok I'll bite. Just my $0.02. Sorry for length in advance.
The answer depends on whether applicant is a nontrad. or traditional.
I believe it is a fair question to ask a nontrad for said purposes because that person has graduated, and having worked in the real world, should be aware that sometimes things don't go according to plan. Therefore, being able to/not able to adjust and deal with these "imperfections" can be indicative of how they will handle the stress of medical school and beyond.
The question is a bit unfair to a traditional pre-med because if the student (without real world working experiences) has had access to good info/fair knowledgeable pre-med advising, then she would have been taught that the level of competition is fierce. Getting top grades are Pavlovian conditioned (rightly or wrongly) into them.
May I suggest another question to gauge perfectionist tendencies. Hypothetically, you (male or female cuz 21st century) spend a year planning the perfect marriage proposal to the love of your life. And you hire a photographer to discreetly photograph the exact moment you propose on a cliff, silhouetted against a setting sun. However, the moment you ask the question and the picture is snapped, you slip and the ring accidentally falls over the cliff. You don't get the perfect snap. Regardless, your SO says yes. What is your response when asked about it later?