The site will be ground Zero for a Russian missile now if war ever breaks out. If not that then other hostiles will show up. No survival shelter is worth much unless its existence is a secret.
In case of a real nuclear war I think I’d head for the nearest target. I’d rather be vaporized than the alternative of dying a slow death from radiation poisoning.
I don’t think the Russians are going to worry about 10,000 prepers in the middle of no-where SD.
As far as the secrecy of your shelter it really kind of matters on the type of disaster that happens.
If you are in your shelter in the middle of no-where when a EMP hits it really doesn’t matter too much if your shelter is well known because any invader is going to take a long time getting there without modern transportation. They will also probably be coming in small numbers
But I agree with you that if you are prepping in your home keep it to your self as much as possible. Your plans should be kept to yourself and your family.