Will Baude and UChicago Prof. Lior Strahilevitz appear to be trying to work out a theory of when pseudonyms ought to be granted to plaintiffs. Baude says, "But the federal claim here wasn't an invasion of privacy claim, it was a wiretapping claim, and I certainly do not think there should be a general rule that wiretapped plaintiffs can claim an anonymity that the rest of us cannot when litigating." This strikes me as a rather technical point; if the plaintiff -- in this case, a 16-year-old who was videotaped without her consent having sex with the defendant -- should be accorded anonymity in her state claim of invasion of privacy, then surely that should be extended to her wiretapping claim as well. Judges who find the former claim frivolous can toss it and make the entire suit named.
However, there also clearly is no simple rule that in cases involving an invasion of privacy, the plaintiff will proceed under a pseudonym, and in any other type of case, he will not. I previously considered this issue in a post about Moe v. Doe, the briefly notorious case in which a man sued his female partner for an injury she inflicted during sex. Neither party said anything about an invasion of privacy, but being understandably shy about having their names publicized in such a proceeding, they presumably petitioned for and were granted pseudonyms. This was a state court case, so FRCP 10(a) doesn't apply, but Roe v. Wade is only the most famous instance of a federal claim brought anonymously.