This NYT story explores why it isn't so easy to do.

An excerpt:

With some of Hollywood's biggest stars pressing law enforcement officials to crack down on the most aggressive paparazzi, a skeptic might ask, is this the best use of the police? Why don't those wealthy actors, with their Beverly Hills lawyers, simply sue anyone who poses a threat?

The simple answer is, it isn't so simple.

"Many times, you never get the ID," said John H. Lavely Jr., a lawyer for Cameron Diaz, Justin Timberlake and other celebrities. Like anyone else, he said, stars in their cars find it difficult to write down license plate numbers while trying to avoid a collision with paparazzi in pursuit.

Even when stars are able to identify the offenders, Mr. Lavely said, the photographers are often "judgment proof" - low-paid, poorly educated immigrants with no resources to go after in a lawsuit. Their bosses often operate out of their cars, with no permanent address, making it difficult to serve them with legal papers. Besides, he said, they typically try to dodge liability by saying the photographers were violating company policy if they misbehaved.

The story noted one star, Justin "wardrobe malfunction" Timberlake, got a restraining order against Artemus Lister, keeping the paparrazo at least 50 yards away. Lister's career, such as it is, was ended.

But would a restraining order deter other photographers from being aggressive, or stop would-be paparazzi from getting into the business?

"Being a paparazzi makes you part of Hollywood," Mr. Lister scoffed. "And everyone wants to be part of Hollywood."