I recently learned that adding a user to a Proof only gives them access to see the Proof and not the document. This means that if you create a file and send a Proof to your client to review and approve. After they make their decision, they have no way of getting back to that document unless they have saved the email and the Proof hasn't been achieved.
My stakeholders were very confused (and so was I) when they went to the Project and there were zero Documents attached. I soon learned that sharing a Proof only shares the Proof and regretfully had to tell my 500+ users that they need to do "double work" and "share twice"
