For some reasons i still believe that there is little that can be done just by holding someone documents as a scammed copy juat as we do when conducting kyc and in some cases during kyc you may be asked to authenticate some aspects which if you are not the original owner of such a document you wont be able to authenticate it and that make such document useless in the hand of the wrong person.
You are severely underestimating scammers. Didn't you hear about the rise of identity fraud across the world? Some places do ask for authentication of those documents, but some places don't and there lies the problem.
This is why privacy is such a big deal these says and submitting KYC at any crypto gambling site regardless of its reputation is risky to varying extents regardless of its reputation.