ip-echelon.com are idiots
As someone that runs a Tor exit, I get regular missives from ip-echelon.com, telling me that I need to deal with copyright violating users.
As a result, I have an SMTP-time block rule telling them to sod off -- they never reply to mails, despite claiming to have a ticketing system.
I seriously doubt that anyone has ever succeeded in sharing a movie (their repeated claim) via my 5Mbit/s Tor exit, so would agree that there is no proper effort to establish infringement by these dodgy lawyers.
What is presumably actually going on is that the client is advertising an allegedly infringing file via Tor, but the infringement (if there is any) is going on via a non-Tor transport. That being the case, their claim of the infringement as being related to my Tor exit is drivel.
They just assume that if a client is advertising a file, it must a) have a copy of the file, and b) be willing to share it, c) have enough bandwidth to actually share it, and d) have at some point done so.
They might as well assume that all Internet users are infringing copyright.