In addition to that, for those people who are still and are planning to sell their identities through verifying different accounts (such as casino account, social media, exchange accounts, etc.) worst is to give documents and verification photos to anyone specially whom that  are unknown for them, you do not want yourself to get in trouble as if those people you've transacted with might have shady transactions being done.
To hide their identity. This is one of the major reasons why people ask others to verify an account using their name.