most of the well known people among those guys have security clearances to be able to work with US gov. which means they are under obligation to report on a regular basis about the people they meet. which means we can say they are part of the "intelligence community" (or if we are less charitable we can call them snitches)
If you have contact with an agent of a foreign power, you're required to report the encounter and what you talked about.
I'm not really sure how agents, or contact, are defined. I think the law is intended to keep IC people honest and forthcoming about foreign attempts to turn people.
(Disclaimer: I have never held a security clearance.)