CRM Marketing Campaign - Polite Footer idea

My boss came across this from a marketing email he received from a Management Company. Rather than the standard usual style unsubscribe footer, they had this:

"We were kindly given your e-mail address and contact details when we telephoned your office. Thank you for being one of the 93% who have not (yet!) asked to be deleted from our database. However, if you would not like to receive any more information from us please click here."

What a great, innovative approach!