Could you use a unionfs like overlay2 for more advanced pid hiding?

Interesting. What are the legitimate use cases to not treat /proc as readonly, and what are legitimate use cases to mount around and especially bind-mount random filesystems around in /proc?

Like, my first impulse is "Why do we allow this?" And I guess, sure, the answer is "root is allowed to do this, because root is never not allowed". And sure I very much dislike my computer telling me "Nay I cannot do that", hence why I have no windows anymore at home.

But there is some stuff that seemingly doesn't have any legitimate use case on a server. And even if protections from that stuff keep me from fixing some situations, I can still nuke and rebuild it in an hour or so.