Finally finished replacing the hangers on this route: the lower 3 where nicked either by climbers outfitting another route or GP offended by the hangers.
I had to climb the back to get to the anchors and rap in so I figure climbers.
Replaced the lower two with powder-coated hangers incase it was GP (though the dynabolts where undamaged).
I peened the ends of the studs to make them harder to remove.
A big thanks to Steve at Rock Hardware for supplying the hangers — he wouldn't let me pay for them!