There is a common misconception among sellers and buyers alike as to what Delivery Confirmation service includes.  The answer lies in the name of the service :)

USPS Delivery Confirmation is just that, confirmation of delivery. It was never intended as proof of mailing or as tracking although those services are available from USPS for an additional fee. As it is a confirmation of delivery, it is only required to be scanned at delivery. That is all USPS promises & is all one should expect. If not scanned at delivery, one may obtain refund of the amount paid for DC when proper paperwork is presented to their local Post Office clerk.

In the event of an Item Not Received PayPal or eBay claim, the only thing that will protect the seller is if the package in question was scanned as being delivered. If package were to be scanned enroute yet not scanned as delivered, PP will likely refund the buyer in full as there is no proof the package was delivered.

USPS says:

"Verify delivery with Delivery Confirmation. Our low cost Delivery Confirmation service gives you the date, ZIP Code™ and the time your article was delivered. If delivery was attempted you will get the date and time of attempted delivery." 

and  
"Services that confirm delivery are designed to be a low cost alternative to full tracking. Instead of seeing the acceptance information and updated scans as the item is enroute delivery confirmation services provide assurance of delivery or of attempted delivery."

I have provided the links to the above pages in my blog: http://blogs.ebay.com/nonie6966/entry/USPS-Delivery-Confirmation-is-not-Tracking/ 

I hope the above info helps to answer questions regarding USPS Delivery Confirmation and that you'll leave me a Yes vote :o)   Please feel free to leave any comments or suggestions on my blog.    

Thanks,
Nonie :o)