After marathon the course closes I like to bike it and see if I can find any leftover GU. There were lots of wrappers this year. However, I found only 5 unopened GU packets. Last year I found 12. So I guess either the GU was mostly consumed this year or cleaned up after the races were over.
There is a still a spot on the course which was not an aid station which has a bunch of orange peels on the ground. I call it orange peel pass. Why no one bothered to clean up the mess I am not sure. In all the excitement of seeing 8000 runners pass they probably forgot.