Actually, the homeowners may have more say than you think. In 1996, when Supreme Scream opened, they complained about the noise the ride was making, got the Mayor involved, and Knott's had to fix it by adding diffusers to the ride. See the article here:
Piping Down at Knott's
And while I couldn't find a news article about it, it's pretty well known that the final turn around on Pony Express was a response to neighborhood noise complaints.
So if they got the city involved again, things could certainly change. It's happened before, twice. And this plan is way, way more extreme (from a resident point of view) than the other two combined.