It's still a crime for a woman to cheat on her husband in Minnesota.

The law against adultery hasn't been enforced in 80 years or more, and it's almost certainly unconstitutional, given that it excludes married men who hook up with single women, not to mention same-sex pairings.

Yet the scarlet letter persists in the law books in Minnesota and many other states. That helps explain the public schadenfreude that greeted the data breach at Ashley Madison, a website that makes money by enabling infidelity.

In this thicket of ironies, here's one more: Former Ashley Madison customers want to sue the company in secret.

For those still unaware of this scandal, Ashley Madison operates as a kind of match.com for those seeking affairs, and claims to have more than 30 million members, many of whom have paid for the service. Earlier this year, a group of hackers calling itself the Impact Team broke into the company's computers, stole data about millions of its customers and put it on online for anyone to see.

Millions of Ashley Madison customers learned that their names, e-mail addresses, phone numbers, sexual fantasies, payment data and other highly sensitive information were now available on the web.

Every large-scale data breach causes chaos, but compared to some of the other major hacks, there has been limited sympathy for the lost privacy of premeditated two-timers.

Still, Ashley Madison promised to protect the data, and properly delete it if a customer with second thoughts paid them $19. So hoped-for class action lawsuits are mounting against Avid Life Media, the Toronto company behind the website.

One of them was filed late last month in Los Angeles. Of the five initial plaintiffs, one hails from Minnesota.

And that's all we know about J. Doe #5. The lawsuit explains: "At this time, Plaintiffs bring this litigation under a pseudonym to prevent public disclosure of their identity and to protect information highly sensitive and personal to them and to prevent further invasion of their privacy."

It's one of the basic principles of our court system that the public knows who's suing whom.

But in this case, it's a "nonissue" because the judge will know who they are, said William Federman, the lawyer in Oklahoma City who represents the plaintiffs.

"It's not something that's often done, but it's done," Federman said. "We will be filing other cases where the people actually want their names disclosed, because they did not utilize the site. Other people are falsely accused. One person doesn't want any more notoriety because she never used the site."

Federman would not say whether J. Doe #5 falls into any of those categories, out of concern it could help identify him: "Clearly he doesn't want a reporter calling him or reading his name in the paper."

The unnamed Minnesotan is not alone. As of Thursday, six other lawsuits have been filed against Avid Life Media since late August, all of them featuring John Doe plaintiffs, federal court records show.

A federal appeals court ruling in 2008 set up the conditions plaintiffs have to meet before being allowed to sue under a pseudonym. The court has to balance the potential for harm to the plaintiffs if their names get out, vs. how it affects the defendant and the public at large.

I inquired with Avid Life Media about how it felt about their anonymous accusers, but received no response. On Aug. 18, the company said in a statement that the hackers' "illegitimate acts … have real consequences for innocent citizens who are simply going about their daily lives. Regardless, if it is your private pictures or your personal thoughts that have slipped into public distribution, no one has the right to pilfer and reveal that information to audiences in search of the lurid, the titillating, and the embarrassing."

Regardless of whether you feel Ashley Madison customers have been wronged, preventing titillation and embarrassment is a lame excuse for turning the courtroom into their private tribunal.

Contact James Eli Shiffer at james.shiffer@startribune.com or 612-673-4116. Read his blog at startribune.com/fulldisclosure.