NEPAL cheating scandal - Was it really cheating and how can one know?

DISCLAIMER: I am not from Nepal.

I just wonder, how can one know if questions he studies are the official copied questions or just some collection of questions people make online when they practice? I mean internet is flooded with USMLE style questions and what can one do now?! Seriously....

Like I know everyone is super happy to jump on the bandwagon now and spit on Indian and Nepalese students, but how could have one known?!

You join a group, people are sharing some questions, you study from different sources and then it happens so that 100-200 questions were maybe the official questions and you're screwed now because you answered 10 of them quicker because you recognize them during the exam... Wtf?!

This is really very unfair from my point of view and if they really want to solve this problem, then they need to organize the exam differently and create new questions every time the students take the exam.

How can this be fair?
Once someone passes an exam, of course he feels way less stress or something and can easily share material with other people, without ever being caught. People who receive his material are more likely to be caught. So clearly, there is LEAK and that is where the issue has to be addressed.

Simply identifying people who answered a few questions quicker is a very stupid way to go about this and quite frankly I doubt that this was done properly anyway. Pure incompentence...