Then why consider a Fail for Creative? The outer envelope teaser: "The information you requested is enclosed." I did not request information from Capital One. The replacement card was not requested. It was automatically sent to replace an expiring card.
On the other hand, Capital One can't paste on the outer envelope "Your new credit card is enclosed." That would invite postal theft. Would a better message be "Important information about your account", or perhaps no message at all?
During my tenure at Citi Cards, we proved through testing that a customer would open just about any mail that was labeled with the Citibank return address. In offers targeting existing customers, a lack of envelope teaser often had the same or better list yield compared to those with a promotional teaser.
Perhaps Capital One believes that for existing card customers branding alone is not enough to ensure an optimal open rate.
Learning: Consider the message on your outer envelope carefully. If you have an active existing customer relationship, you may not need any message. Focus on the message's appropriateness given the contents and recipient.