But your caveats mean that, in practice, they can come after anyone who actually came into contact with the material unless it was dead-dropped to them without

But your caveats mean that, in practice, they can come after anyone who actually came into contact with the material unless it was dead-dropped to them without their knowledge, and even then, maybe they were 'encouraging' it. See Julian Assange. What's his case hinge on again, "conspiracy to commit computer intrusion"? Any amount of working with a source would be such a conspiracy.