Buying internet logs might also be highly illegal in the EU, but IANAL
If it was the police uploading a new torrent and getting people to download it, it might be.
If it’s a private firm that joins the swarm and observes who is seeding, it’s different. They don’t even need to seed anything. Nor download anything. But even if they did it might be ok.
IANAL, TINLA.
You can either join private trackers where they're not allowed to hang out, use a VPN to make you "untraceable" (as far as these petty tyrants are concerned), or both.
Because an IP address is not a mailing address. And they don't buy your internet activity logs. They buy the ISP's log of which IP was associated with which account.
Back then, for those interested: the monitor file sharing networks, download a tiny bit of data from you (uploading is the expensive part in Germany) to prove you upload, go to a judge who will force you ISP to give them the contact, send you an Abmahnung, requesting an Unterlassungserklärung and cash (500 damages, 500 lawyer cost). We just sent a modified "we are not doing damages" letter and ignored any future communication from them. There was more to scare us, but they did not follow through with a lawsuit. Oh and ofc I made sure that no further upload could be detected. Yes there were rulings back then holding the connection-owner legally responsible
Can I ask how you did that?