RobertPatrick wrote:

My cousin works for a financial investment advisor. They are not allowed
to email anything with private information on it, such as a client's SS
number, contract number and so on.

If the email is sent internally using only the company email
server, it will never traverse the public Internet. Add some
encryption, and that's much, much safer than a hard copy. You
could beef it up more by requiring a smart-card or USB dongle with
the decryption key, so the user is required to "know something"
and "possess something" to be authenticated.

Maybe the SEC has guidelines for sending confidential
communications.

Who knows where that piece of paper may end up if misplaced.