A "public nudity" arrest made five years ago could wind up costing San Diego taxpayers a lot of money.

The case centers on a leather loincloth outfit worn – over thong underwear -- by a Hillcrest man during the 2011 LGBT Pride Festival.

The city never brought charges against Will Walters, who fashioned his garb in what he called a “gladiator” style.

But Walters later filed a civil rights lawsuit, alleging selective enforcement by the San Diego Police Dept.

And a federal appeals court has set a December trial date on his claim.

Walters, 35, is hoping to recover more than a million dollars in legal expenses.

That’s because the civil case has climbed the legal ladder all the way up to the 9th U.S. Circuit Court of Appeal, where one of the justices remarked, at the end of a hearing: “Why don’t we just say that was a bad call by a police officer”?

But the city apparently isn't content to leave it there, and settle with Walters.

"I find it sad that in a city as big as San Diego, in a state as progressive as California should be, I still can't get an apology for something that the nation now accepts," Walters said in an interview Monday.

Five years ago, police officers patrolling the Pride Festival saw Walters’ costume legally as unacceptable, and booked him into jail on suspicion of “public nudity”.

City prosecutors never brought the case to court, where jurors would have been shown ample evidence of women's flesh likewise being flashed at local beaches -- and not made subject to police activity.

Selective enforcement, gender discrimination?

Questions for civil jurors to decide.

But Walters, who works in finance, faces a million dollars in legal costs that his friends and lawyers have been fronting -- when, long ago, he might have settled for a sincere apology.

"I have no idea why they didn't just tell me 'We're sorry that we did this to you,” he told NBC 7. “It's incredible."

This observation, from his attorney Christopher Morris: "Most people that have these kinds of things happen to them just have to chalk it up to bias, chalk it up to life experiences and just move on. But Will has the opportunity in this case to stand up for his rights. A right and an opportunity that a lot of people in this country simply don't have."

Now the taxpayers could be on the hook, because Walters is determined to "fight City Hall".

Conversely, however, he could wind up with nothing by taking the case to trial and risking a thumbs-down from the jury.

"In history, everyone has taken a risk to try to achieve equality,” he says. “So I guess it's a risk I'm willing to take."

To some extent, the outcome of the case could hinge on the first order of business -- jury selection, and whether issues of homophobia arise and are addressed.

In response to a request for comment on the case, Gerry Braun, spokesman for City Attorney Jan Goldsmith, provided the following by email:

“Mr. Walters was given a ticket (similar to a traffic ticket) by an officer who believed the outfit violated the law.

“But Mr. Walters refused to sign the ticket committing to appearing in court. So he was taken into custody, just as a motorist would be if the motorist refused to sign a ticket.

“The City Attorney’s office received the case and decided not to prosecute because, although the officer had probable cause, our prosecutors did not believe the case could be proved beyond a reasonable doubt.

“Thus, the matter was over. Mr. Walters decided to sue the city seeking money. The city won a motion for summary judgment. Mr. Walters appealed.

“The appellate court threw out his claims of false arrest and battery. The remaining issue for trial is whether SDPD engaged in selective enforcement.”