After reading the topic, I made the following conclusions. We shouldn't send fake documents, as we are breaking the law in this way. But the KYC check itself is also illegal, as it violates the basic principle of the crypto space - anonymity. But as a result, both things still happen.
You might be breaking tha law but unless the harmed party opens a case, falsification of documents doesn't also mean automatic prosecution. At least not in all jurisdictions.
I think the worst case scenario is that the exchange ceases to offer services to the perpetrator. Perhaps if the false documents were also combined to an individual trying to defraud the exchange or service itself, then a case is more likely to be opened. But otherwise I don't see a realistic way that the "illegal" part could be that serious. Exchanges get fake KYC all the time. They only care about it once they're told about it because they can't "knowingly" accept it. But even then, all they do is close the account for trading. These users that had fake KYC might try all over again.