Is this enforceable?

We have all received emails from consulting firms and law firms with the following type of message printed at the bottom:

This message (including any attachments) contains confidential information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, you should delete this message. Any disclosure, copying, or distribution of this message, or the taking of any action based on it, is strictly prohibited.

A question for the lawyers out there:  Can someone from another organization who mistakenly sends me a message bind me to this prohibition?  If I never requested the information, I can't see why I have any such obligations or how I can be held responsible if it was their action that released the information.

Note:  I am not talking about patient-specific information or other stuff protect by HIPAA.  The most recent example to cross my desk was a general mailing from a consulting firm giving their appraisals of public policy issues in the health care field.