The justices found that police who carry out such media outings can be sued for violating the Fourth Amendment's ban on unreasonable searches and seizures. What's still to be decided is if the journalists can be charged as well.
Chief Justice William Rehnquist, writing for the court in cases from Maryland and Montana, cited the "centuries-old principle of respect for the privacy of the home."
"Surely the possibility of good public relations for the police is simply not enough, standing alone, to justify the ride-along intrusion into a private home," he wrote.
The American Civil Liberties Union said the ruling means police must be guided by the Fourth Amendment, not by the demands of the "infotainment" industry.
"The government is not allowed to make a display of you," added Joshua Dratel of the National Association of Criminal Defense Lawyers. The group supported a Montana couple who sued after government agents brought along a CNN camera crew while conducting a raid on their ranch.
The Supreme Court looked at two cases where law enforcement agencies took journalists along during the execution of search warrants. Media lawyers had argued that reporters provide a public service by documenting police work.
One of the best known reality shows, Cops, says the ruling doesn't pull the plug on them because they get permission from everyone involved. But legal experts warn shooting first and getting permission later could still mean trouble.
The ruling still will allow the media to accompany police officers as long as journalists stay outside when officers enter private homes.
The scene is repeated countless times daily across America: Police officers burst into a house or some other private place in search of a quarry. A court-issued warrant or emergency circumstances give police that authority, but the justices said bringing along outsiders is another matter.
Despite that holding, the justices ruled 8-1 that the police officers in the two cases they reviewed cannot be sued because it was not clearly established when the raids occurred that such access was unlawful.
In the Maryland case, Montgomery County sheriff's deputies and deputy U.S. marshals took along a Washington Post reporter and photographer when they entered Charles and Geraldine Wilson's home in Rockville early one morning.
The officers wanted to arrest the Wilsons' fugitive adult son, who was not at their home but turned himself in later at his parents' urging.
Paul and Erma Berger filed the Montana case against federal agents and a prosecutor who let a CNN reporter and camera crew accompany them to the couple's ranch. Government agents were seeking evidence of eagle poisoning, but Paul Berger was convicted only of improper use of a pesticide, a minor offene. CNN later aired footage of the raid.
When the cases were argued before the court in March, most of the justices seemed determined to stop police from continuing the practice. At one point, Justice Sandra Day O'Connor called one such raid "an amazing invasion." Justice David H. Souter agreed saying, "I don't see why you have to take the news media people into someone's home. ... It sounds like fluff."