Please read it very careful and note the words, SEEDS and Exposed

"Nothing in the regulations prohibits you from hunting waterfowl in wildlife food plots, including those planted with millet, unless the seed has been freshly distributed, scattered, or exposed. "

This is where it becomes a Judgement Call on the part of the Warden. If you can't see seeds, your most likely safe, but them again it's the Warden or SA call. Good Luck.