This summer while crossing Lake Ontario out of Oswego we were boarded by CG. It was for training just like Ted's experience. I stayed at the helm while the wife showed all the inspections items. We have a discharge plaque at the lower helm. The young CG fella said we needed a "waste management plan". He told her to get a pen and paper. He proceeded to dictate a plan while my wife wrote down what he said. It basically said we would segregate all trash and properly dispose when we were ashore. It sounded bogus to me but it was easier to get them off the boat as fast as possible. They were very friendly and the experience wasn't bad. The wife wasn't pleased that their big black boots marked up her wool rug in the salon.
I believe West Marine gives those signs away for free or you can buy nicer versions.
I have them but forget where they are when it comes time to show them. The whole idea of a sign seems pretty silly. We all know what we're supposed to do but we're going to do what we want regardless of a sign.