The Proof settings tab .(_____my.workfront.adobe.com/proof/account/settings) has a section called Pop-up Messages on proofs. The section description says that "The proof messages appear when the proof first opens ("On load") or when a person makes a decision ("On decision"). You can use the "On load" message to explain to users how to review a proof or provide disclaimer or other legal text. You can use the "On decision" message to give your users checklists for things such as brand or regulatory compliance."
This functionality definitely isn't for everyone since many companies and many working teams have more specific directions that need to be given. But you do mention "every time we send a proof" so I wanted you to know that was an option. The user still has to open the proof to see whatever direction you have, so it still has some limitations (you can't use it to direct the user how to open a proof).
