If you are doing something illegal (according to the laws of the country where you live), then you cannot even expect a different outcome from what just happened to these Nepalese. Their age shows that they are young and inexperienced people, and they probably came under the radar because they did not try to hide from the authorities at all, and it is not difficult to connect points that include only the bank and crypto exchange.

If people in Nepal want to trade crypto, then unfortunately they have to be smarter than the authorities - which means looking for ways that do not involve domestic banks and KYC on crypto exchanges.