Is flashing your car’s headlights protected by the First Amendment?
Missouri resident Michael Elli wanted to let others on the road know to slow down because they were about to drive into a speed trap, so he did what many kindhearted souls do: He flashed his headlights as a warning.
Police didn’t take at all kindly to warnings of this 21st century Paul Revere. They flashed him a ticket of his very own for obstruction of justice. Prosecutors eventually dropped the case, but Mr. Elli has now filed a class action lawsuit against the city because he says that the city retaliates against drivers who exercise their right to free speech–and that the government is trying to prevent it because it doesn’t like the message.
Under the law, obstruction of justice is generally defined as an attempt to interfere with the administration of the courts, the judicial system or law enforcement officers.
So if a person is aware of a confidential, ongoing investigation and tells the subject of the pending investigation, he or she may be guilty of obstruction of justice.
A former Key West bank officer pleaded guilty this past May to a charge that she received a grand jury subpoena, was told that it is a federal crime to disclose a federal grand jury subpoena received by a financial institution, but notified the subjects of the investigation. She faces up to five years in prison for the violation.
http://news.yahoo.com/flashing-car-headlights-protected-first-amendment-103216345.html
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I've been using a GPS deal on my phone called "Waze"; it's a clever premise, whereby users transmit data to one another about traffic, allowing the program to design real-time routes to avoid jams.
One of the features is the ability to manually note obstructions on the road or shoulder, such as debris, stalled cars, or police cruisers. They show up on the map --designated as "visible" or "hidden" -- as little cop hats. 
