Just off the top of my head, they could be using the evidence of a person donating to a torrent group as probable cause to see what other illegal activity that person has been up to…
I was mostly joking in response to why a torrent tracker would be asking for donations in a cryptocurrency that can be traced…
Inside the pot: slowly boiling water
Outside the pot: raging inferno that is heating the pot
When given the option to slowly boil, or jump into a raging inferno, I think most people would think twice about jumping out of the pot.