Have you ever flashed your headlights to warn a fellow driver about a nearby speed trap? It may seem like an acceptable (and often commendable) action, but when Mark Zaid did that recently in Montgomery County, Md., he was pulled over and ticketed for the offense.

That’s right, a police officer stopped him and issued a $50 citation, saying that flashing headlights in Maryland was illegal and Zaid could even be charged with “obstruction of justice” for warning fellow motorists about the speed trap.

The Washington Post reported that Zaid makes his living as a lawyer for government whistleblowers and believes he did nothing wrong: ”The more I thought about it, I realized I’m going to make an issue of this.” Zaid, therefore, showed up for his court date to protest.

Montgomery County police said state law prohibits driving with “flashing lights,” but the ACLU of Maryland drew a line between “flashing” and “flashing.” The ACLU said the law applies to flashing as an adjective (an emergency blinker is a flashing light), but not as a verb (flashing your lights to communicate briefly).

Are you confused? Well, don’t be. The officer, who had also ticketed other drivers at the speed trap, was on military leave at the time of the court hearing to decide the matter, so the judge simply threw out the charges.

The moral of the story: Apparently in Maryland you can flash your turned-on headlights, but you can’t turn on flashing headlights.