When Disclaimers Attack

I’m seeing more email with disclaimers at the bottom.
This e-mail and any files transmitted with it are the property of $companyname, are confidential, and are intended solely for the use of the individual or entity to whom this e-mail is addressed. If you are not one of the named recipient(s) or otherwise have reason to believe that you have received this message in error, please notify the sender at xxx-xxx-xxxx and delete this message immediately from your computer. Any other use, retention, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited.
Lawyers gone wild. As Information Security Professionals we are supposed to yield to the domain experts. The problem is often the legal guys are in their own world.
This seems like an example of doing SOMETHING in the name of security, but not being sure of actually accomplishing anything. I feel like I should immediately delete the email, scrub my exchange server, reboot the routers to remove any possible remnants, call my lawyer and my company contracts office, and just in case stop accepting any new mail.
Do disclaimers at the bottom carry any legal weight? Its kind of doubtful. I mean to have a contract dont both sides need to have consideration? I have heard of one case where it was important for the disclaimer footer to warn that email traffic is monitored at company X. that way if [email protected] sends email to [email protected] she knows not to be sending illegal material back to [email protected]