The way they catch you is by downloading a complete “Linux ISO” you seeded. Their log from that download shows your IP and that’s the evidence.
So either don’t seed a complete “ISO”, or use a VPN from a provider that will laugh at info requests from German lawyers.
Safest way is to make sure you only torrent Linux ISOs that can be legally shared according to their copyright license, of course ;)
Yes, I hired a lawyer for consultation.
Since I was very poor at the time, I could get the cost for it reimbursed from the state, after laying bare my finances in front of a judge.
As for the seriousness, the legal firm moving against me had opened a case before a court in Munich (500km from where I lived) and I had to plead my case in writing to the court.
Next step after a lot of legalese back and forth would have been a summons before the court in person, which didn’t happen. The letters just stopped.
In the end, I paid 60€ for fees and postage. They had wanted me to pay 2000€ to settle and my lawyer told me if it goes before a judge, worst probable outcome would have been 600€ in court and lawyer fees.