All federated systems are centralized at core. That just means they would subpoena all servers, but they could just grab and take whatever they can get hold of, no warrants, no subpoenas. That also means there will be levels of data security depending on how well or bad each node is secured. Some would be easy to get some not.
Bittorrent is decentralized but trackers are centralized we have seen how much trouble they are facing to keep themselves up. And it is just hollywood vs pirates, had it been state they would already be grabbed, sealed and analyzed.