I've been by the dunes in Oregon about 15 years ago on a road trip, and have wanted to go play there, but because of what you just wrote, that I've heard from other people...I'm not so sure I'd like to.
Isn't the sound restriction only because there are houses built next to the sand? I can't imagine its to preserve some sort of butterfly, or to perhaps ease the stress on the trees or something.
They need to just pass out earplugs on weekends to the people in the houses.
Here, people have built houses next to 1) the city/county garbage burn plant, 2) the city/county garbage dump, and 3) Hill Air Force Base, then they have the fuckin balls to complain about the noise and or the smell.
If you have a house next to some sand dunes, chances are its going to get noisy.