The problem in admission is that some universities look at your GMAT in a prejudicial way, for instance when there are many applicants who get high GMAT scores apply with you, this will reduce your chances as universities consider GMAT to be highly representative of your abilities unfortunately.
It's not prejudice. A strong score on the GMAT is a great predictor of success in an MBA program. If you get a low score, then admissions people have every right to question whether or not you will succeed.
Fortunately, admissions committees tend to be smart about these things and if you do score low they'll look at other parts of your profile to see if there are other indicators that you'll be successful in the MBA program. Let's look at this candidate in particular:
1. 540 GMAT score: this score is under the 50th percentile of all applicants who take the GMAT, so it's unlikely that s/he will do as well or better than most other candidates. So let's look at other parts of the application to see if we've overlooked something.
2. 2.1 GPA, which is lower than a B average. For some reason, this candidate did not do as well as most people who are successfully admitted to MBA programs, so that's another red flag. Perhaps there was some underlying cause for poor performance, which could be compensated for with fantastic work experience or demonstrated leadership skills. So let's look at that.
3. Just over 2 years of work experience. Well, that's really just above the bare minimum, and really not enough time to demonstrate the growth and leadership skills that could compensate for poor undergraduate performance and a low GMAT score.
So it's not entirely about the low GMAT score, it's that this candidate is underperforming on pretty much every aspect. But of course there are many things that can be done, including retaking the GMAT, getting more work experience, and filling out his/her profile in other ways.