There's a good chance this is true: I'm going off what I was told, which being that I was at a government contractor was probably largely FUD because they didn't want me doing anything that would jeopardize their business (I may not have ended up in jail but I would have cost them a lot of money and probably would have been fired).
Somebody much more knowledgeable than me can chime in on this.
Yeah, and if it was a defense contractor, its quite likely that a substantial number of people (maybe everyone) in the firm may have actually been subject to the kind of rules you describe, even when most citizens are not.
There appears to be a large gulf between what the government advises its employees and citizens about handling classified information and what criminal charges and/or adverse administrative actions it can sustain in the face of legal scrutiny.
Classification is provided by the government, internal to the government ergo a citizen that is neither government nor contractually associated with said government can read anything they like.
Somebody much more knowledgeable than me can chime in on this.