I printed a label from PBS with delivery confirmation, but put my own postage on it, then dropped it off at the local post office.  I thought it was odd that I never got the book credit when they scanned the DC.  Why?  Because they apparently never scanned it.  The receiver of the book let me know that when he received the book, the DC bar code was blacked-out with a permanent marker.

I suppose I should be grateful the postage wasn't blacked-out and the requestor receive the book with postage due...

Bummer Sec, another untrained postal worker.  You might wish to consider printing another copy of your mailing label, taking it to the local post office, tell the postmaster (not a clerk) how much postage was applied and ask what happened. 

Mailing that way should not have been any problem.  Honestly, we've heard so many variations on this theme I'm starting to think USPS needs to ban the use of black markers by their employees.  Too many have become over-eager to deface legitmate and legal electronic DC.

ETA - oh hey, there's an idea I should propose to USPS.  A competency certification, employees only receive a black marker after passing a certain level of training...like the ability to recognize (and correctly process) electronic delivery confirmation.

Sharpie Certified...  ha!  But at this post office, probably necessary.  Never had a problem at the post offices where I used to live -- those folks knew their stuff and would bend over backwards to help you.

Now, well, I'm just trying to get my packages through while avoiding the dreaded Sharpie of doom.

". . . the dreaded Sharpie of doom."  ROFL sec!

did you add enough postage to cover the DC? even though you pay PBS, you still have to pay  an additional  DC fee on media mail and parcel post at the PO. If you only paid for the cost of the postage and not the DC then they were right to mark through it.

Yep, proper postage was paid to cover DC...  A postal worker rang it up and I paid at the counter.  That's why this is so bizarre.

When I said in in OP that I "put my own postage on it", I just meant I didn't use PBS to print the postage.  (In hindsight, I wish I would have.)

If you purchased counter postage, I'd be double unset (and demanding answers).  There's no excuse for that, why would they even check a package that had counter postage on it...don't trust their own staff?

Definately a vendetta by the 'Marker OCD' employee.

I don't use DC that often but whenever I have and bought counter postage, they scanned it right then to get the right fee added.

I'm with Mary -- if they don't scan it, they'll charge you the full price for DC, which is significantly more than we pay.  Maybe the employee just missed the DC barcode and only charged you for media mail? 

Was the package really thin and floppy? There are some requirements on size in order to use Delivery Confirmation and if your package did not meet them they would black out the DC.

eta the info from the Help Center:

Are there any requirements to use Delivery Confirmation?