Problem scenario
You received an email that you should not have. The footer requests you let the sender know and delete the copy you received. What should you do?
Solution
We think you should not examine the contents closely, delete the email and let the sender know. There may be a disclaimer boilerplate in the email that may or may not have legal weight. Even if there is no such disclaimer on this accidental email, you will be proud that you respected the confidentiality and privacy of another party. Treating other people as you would like to be treated can give you moral high ground. Being polite and sensitive can help you in the long run. Forwarding it on or disclosing the contents of the email may be bad manners.
It is advisable to have in your long-term memory a disposition to honoring commitments to the privacy of others. Mistakes happen.
For more information, and some mixed treatment, about such email footer disclosures, see this.