Have email disclaimers gone mad?

It might just be karmic justice. Until a few months ago I worked at a company that would like to redefine email as Email 3.0 or something - the product was an email gateway that added branding, business cards, and also those stupid page-long disclaimers.

On Monday I bought a little baby PV solar panel, just to have an electronics guinea pig. Setsolar asked me for my address, email and real life, phone number, all sorts of things. (I wasn't in the mood to kick up much of a fuss.) So today I received the tax invoice by email. Fair enough, and kudos to them for allowing '+' in an email address. But then... there it was, lurking at the bottom of the email (emphasis mine):

Confidentiality Note: This email message and it’s [sic] attachments are the property of SETSOLAR. This information is intended solely for the attention and use of the individual or entity to which it is addressed and may contain confidential and legally privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.

WTF? Since when is an invoice the property of the vendor? And just when did I agree to a contract that seeks to "prohibit" me from unauthorized "review" (???), use, disclosure and distribution? I guess I should now expect NPA to come knocking at my door.