I've only missed PDB's 2x this year so it has been a real good average but on my most recent trip, 2 legs didn't have it so I sent in a note via the DL website. I let them know I was doing it as an "awareness issue" for Delta and didn't ask for any compensation, though they did throw 5K miles into my account.

I think that since Delta has stated that PDBs are the goal, sending them a note when it doesn't happen is the way to go. Don't see how they can correct it if they are unaware.