I'm happy Cas is back and all that but my question is this:
What about the symbols Cas carved onto Sam & Dean's ribs back in 5x01 to hide them from the angels?
Those kept them hidden from all angels, including Cas and Lucifer himself all of Season 5. They had to use a cell phone all season long to contact Cas. I can understand Sam maybe not having them anymore after being in the pit and then being resurrected from there by whoever is responsible, but that wouldn't explain what happened to the ones on Dean's ribs.
Edit: Here's the dialog from 5x01 where Castiel explains the carvings:
DEAN: What the hell was that?
CASTIEL: An Enochian sigil. It'll hide you from every angel in creation, including Lucifer.
DEAN: What, did you just brand us with it?
CASTIEL: No. I carved it into your ribs.
Theories, ideas anyone?