Sending out documents by attaching a file in the email or envelope?

What if, due to fatigue, SP [A] documents or files is attached to SP [B] in an envelope or email address?
The SP that received others SP reports or documents will be unhappy. If this can happen to others, it can happen to me that you send my details to another SP? You will have a lot of explaining to do.
What is the control that is in place to prevent sending the wrong files and chances of sending the wrong file even if the control is in place?
Human error is unavoidable regardless of how much control is in place. Automation comes in that will greatly reduce this error.
Our auto-email will pull the selected document to the relevant SP. The first line of control is to make sure that the email address is placed correctly in each SP account.