If you have a top-notch GMAT score and stellar work background -- you're the son of an international conglomerate ready to take over as president -- and you apply to a competitive, but albeit 2nd tier school that is still selective---then it definitely makes sense for adcom to reject you. After all, someone like you can clear get into a higher-tier school so why should they waste an admissions spot on someone like you who isn't a good fit for the school.
Oftentimes, schools want to gauge what the probability of you accepting an offer from that school. It would make the school look bad, if they gave offers to every stellar candidate -- but then all of them reject that offer. These % acceptance of offer rates are published in all the rankings. So business schools need to protect their image.
That's why if you are on the higher end in terms of credentials, etc --- make sure you show a genuine interest in that particular school. Show them that there is a high probability that you would accept an offer from them if given the opportunity. You do that with little stories here and there -- especially in the interview -- but also in your essays.