How? The term "prior art" already only applies to publicly-disclosed knowledge. Trade secrets don't invalidate patents, since part of the purpose of patents is to dissuade people from keeping inventions secret. If you want to be protected from someone else inventing and patenting your invention, you have to disclose your work, such as in your own patent application.

That doesn't really feel relevant to what I said. People in the comments here have given a few situations in which participating in this could be disadvantageous. I am sure there are more.

But specifically, how do you think an NDA could interfere with this?

I'm not allowed to talk about this kickass technology my company is using, not even to dispute a patent claim my competitor is making.

I'm not allowed to post a question on this site because I can't talk about the technology my company is using.

I'm not allowed to post prior art on this patent because it might reveal how my company is solving problem x, a problem plaguing most of my competition and were they to figure it out, I'd lose some edge in my market.

I can come up with more if you'd like.