I can appreciate your hard feelings after all your work tanked. This is precisely why the total NUMBER of hunters has to be controlled. With fewer folks out there, there is less competition for the scarce resource - they can bust a different flock, not the one you're scouting. However, I would not view this as an issue with ethics. They hunt different from you, and stepped on your toes. Doesn't make them evil or unethical- it's just the nature of competition and conflict. Reducing numbers of hunters will reduce the competition, and your feelings won't get hurt as often.
Evenmore, I agree with Tom about water hunting. I consider "shooting the roost" -- hunting birds when they return to their evening safety spot -- illegal for geese, by proclamation, for most of our season. Birds "roost" (verb) when they find a safe spot for the evening. It remains a very effective and common way to hunt ducks. Otherwise, hunting geese on water is just another alternative to hunting them on land. Sure, its more competition for you, but hardly evil, unethical, or wrong.
It's terrible, but we're spending more of our efforts adapting to the competition of other hunters, rather than in competition with our quarry.