DGTV has a great picture of a putt that is in question.
I am looking at the rules and to me, it looks like its in. From 803.13 Holing Out:
B. Disc Entrapment Devices: In order to hole out, the thrower must release the disc and it must come to rest supported by the chains or within one of the entrapment sections. This includes a disc wedged into or hanging from the lower entrapment section but excludes a disc resting on top of, or hanging outside of, the upper entrapment section. The disc must also remain within the chains or entrapment sections until removed.
There is no mention about the disc resting on the basket and another object. My guess is that the author never imagined the basket being this close to a rock.