> What if someone (perhaps a political campaign or party) with some kind of vested interest and a whole lot of money broke off a couple hundred dollars for a few hundred people?

If those people are OK with committing a felony for a few hundred dollars, ok, but I doubt most people would even entertain the idea.

It's a huge risk, a personal risk, and takes a large number of people who all have to be trusted.

And then any NDA they sign will be made irrelevant as soon as one of them gets immunity for testifying against the organizer in what would inevitably become a RICO case.