I've seen a LOT of WotC and Paizo maps with elements dropped in from Campaign Cartographer. I imagine they BUILD the maps in CC2 or 3 and then save them out to image file and load it into photoshop and hand draw over it.

Go back to the last few issues of Dungeon Magazine before they stopped printing them and you'll see lots of CD2 buildings...I even posted a thread about it here a while back when I noticed it.