When Irma Matos leased her Porsche sports car, she had no idea the headlights were coveted by thieves—not until the three sets were stolen.

Exasperated, she terminated her lease early and traded her Porsche for a BMW.

Luis Alayo-Riera knew about the thefts. The self-described “Porsche fanatic” was attracted by the high-intensity discharge headlights, took measures to protect the vehicle and eventually sold the car at no diminished value because of the problems.

Both were members of a class-action lawsuit against Porsche Cars North America Inc., the distributor of the prestigious German-made speedster.

The Third District Court of Appeal in Miami on Wednesday decertified the class action brought by up to 1,000 Porsche 911, Boxster and Cayman cars in South Florida, saying a circuit judge used an outdated definition of unfair trade practices when allowing certification.

The rub was that some of the plaintiffs, like Alayo-Riera, knew the headlights were easily stolen.

In their claim, the class representatives asserted unfair trade practice and unjust enrichment claims in suing the Porsche distributor, blaming the company for not taking remedial steps.

Coral Gables experienced a tide of headlight thefts, and Porsches were disproportionately targeted. There were 483 headlights stolen from cars in the city from 2002 to 2010—226 from Porsche vehicles.

The 22-page opinion by Judge Thomas Logue said Miami-Dade Circuit Judge David C. Miller adopted an outdated premise that the distributor’s action can be found to violate the state’s unfair trade practices law regardless of whether class members knew and could have avoided headlight thefts.

“To prove an unfair trade practice, the class must prove that the injury caused by the allegedly unfair trade practice could not have been reasonably avoided by the consumers,” Logue said.

He said the unjust enrichment claim also was faulty.

“A court would be hard-pressed to conclude the distributor was unjustly enriched when class members with the sophistication and knowledge of Alayo-Riera continued to seek out the headlights even when they knew of the thefts,” he wrote.

Judges Vance E. Salter and Barbara Lagoa concurred on the opinion.

A call and email to a spokesman for the Porsche distributor was not returned by deadline.

Attorneys Douglas Eaton and William G. Wolk, partners at Eaton & Wolk in Miami, represented the class and is considering their options.

Eaton said the decision adopts a federal standard on whether consumers can reasonably avoid the alleged harm, but the Florida Legislature has never adopted that standard and every state court has followed suit.

“The Third District Court has decided those courts were wrong,” Eaton said.