This means that anyone who uses freenet can have a warrant against them. I would attack the warrant itself. From what I remember about freenet (it's been many years since I looked into it), plausible deniability is given because each node is requesting keys that another node requested. For instance, if node A wants file X, then A will request X from B, C, and D, who will in turn request it from more nodes, and no one knows who the original requester was. So every person on freenet is holding a cache of data that other nodes have requested, and has no idea what was requested, and are themselves requesting files on behalf of other nodes which they have no idea about.

In summary, if you are on freenet, you are not only requesting your own files, but files on behalf of others, some of which could potentially be illegal material.

If being on freenet and requesting a key (even for someone else) is enough to get a warrant, all people using freenet from a traceable IP should immediately get off freenet.

I don't know anyone who uses it, I thought tor superseded it, but this sets a very dangerous precedent. The defense should be reaching out to a computer scientist who can explain the fundamentals to the court.