On July 17, New York porn producer Lucas Entertainment filed a federal lawsuit against 65 alleged file-sharers who were swapping copies of its film Missing after using the gay-torrents.net BitTorrent index. But, as in most of these cases, Lucas didn't actually know who the 65 people were. It had an IP address and little else—so it went to court and obtained subpoenas for the ISPs who handed out those addresses to subscribers.

This has become an increasingly common practice in recent years—the RIAA used it for its lawsuit campaign, the US Copyright Group is currently going after 14,000+ people with the same technique, and Lucas itself has filed two such (smaller) suits in the last month to protect its porn. In numerous cases, the targets of these inquiries have written to the judge, asking for the subpoena in question to be quashed and for their anonymity to be preserved.

Unfortunately, these targets also have a tendency to put their names and home addresses on this correspondence, often including copies of their IP addresses for good measure. It happened again last week in Lucas' lawsuit about Missing, where a man from Connecticut named Donald M. included all the information being sought about him in his attempt to keep that information from being revealed. The federal court's publicly available PACER system now contains a scan of Donald's letter, signature, and envelope, complete with home address.

Donald provides no real reason for the judge to quash the subpoena, and such letters have been almost universally unsuccessful (quashing a subpoena isn't about asserting one's innocence). While his attempt will likely fail, his letter also reminds us that these sort of copyright dragnet operations routinely sweep up people who are baffled at what is happening to them.

"I write this letter to formally oppose the order allowing Charter Communications to disclose any information of mine," writes Donald. "I do not know what this is about and the documents forwarded by plaintiff's counsel were of such poor quality that they were nearly impossible to read."

Though Donald did keep his IP address out of this request, the lawsuit targets only two Charter users. Inputting both of those IP address into geolocation tools shows that one is assigned somewhere in Michigan; the other is distributed in the very city where Donald's letter was posted. In other words, Donald, seeking to keep his identity private, has revealed himself to be Doe #57, an alleged uTorrent 2.0.2 user who was downloading gay porn on July 17.

Of course, an IP address doesn't identify a person or even (in most cases) a particular machine; it only points to a subscriber account, one that could have been used by a friend, guest, or family member.

Those who do wish to challenge a subpoena would be better off doing it anonymously, as several defendants in the US Copyright Group cases have done. Simply asking a judge to preserve one's anonymity can be enough (though, when that motion to quash fails, your identity will be exposed anyway).

Why don't people avoid these sorts of elementary mistakes by hiring a lawyer? Cost. As one lawyer defending people in these sorts of cases told us this week, "One of the major problems that people encounter when trying to hire me on these cases, is that a settlement is approximately what an attorney would need to even begin a defense!" Economically, it may make sense to settle up and just make the problem go away.

For those inclined to pursue their own defense in these sorts of cases, Florida lawyer Graham Syfert has created three documents that defendants can purchase for $99 (update: this now appears to be $9.99). "My dream would be to have 10,000-20,000 people file all three documents to the lawyers and severely cripple the entire process and show them that you shouldn't be allowed to join so many defendants," he tells Ars.

To date, though, few pro se defendants have had much success at quashing subpoenas. Questions about jurisdiction and joinder may be next on the agenda in many of these suits, but those depend in large part on how the different firms elect to proceed with their lawsuits.