Some Los Angeles Kings fans were celebrating the team's Stanley Cup win outside the Staples Center last week when they noticed a Phantom-model quadcopter drone buzzing above, surveying the scene.
Angry at the intrusion, they knocked it down using a T-shirt and smashed it into bits with a skateboard.
What remains of the drone is sitting in a Los Angeles Police Department property room, waiting for its owner to claim it. If the owner steps forward, police will give him back his drone but do little else. Flying a drone in public is not illegal, police concluded.
"It was kind of an eye-opener for us that this is something we really need to pay attention to," said LAPD Cmdr. Andrew Smith about the drone outside the Kings game. "It's certainly something that's growing enormously."
Drone use is becoming an issue as the unmanned aircraft become more popular, especially as a way for hobbyists to create videos. YouTube is filled with drone videos taking in the views of Yosemite, prompting rangers last month to issue a public notice saying the machines are banned. At the Grand Canyon recently, a drone crashed, stunning visitors who were there to take in the sunset.
On Friday, the National Parks Service announced that it intended to ban low-flying drones on the 84 million acres of land it manages, citing concerns about visitor safety and the impact on wildlife.
Other drone-filmed videos are also popping up that show sporting events, local beaches and even DUI checkpoints.
Although the Federal Aviation Administration has a host of regulations about how private businesses and law enforcement can use drones, there are few rules covering the casual hobbyist.
A ruling by a federal oversight committee in March further complicated regulation. The National Transportation Safety Board's Office of Administrative Law Judges found in favor of a pilot who was issued a $10,000 citation for flying a drone over the University of Virginia as part of a photography project. The FAA is appealing the ruling.
The FAA estimated in a report that there could be 7,500 civilian hobbyist drones in use within 5 years. Federal officials said they hope to craft clearer civilian drone rules by 2015, but some experts said that's too optimistic a timeline.
The rise in civilian drone use comes as prices for the aircraft decline. Prices now range from a few hundred to a few thousand dollars.
Torrance resident Daniel Saulmon, 42, has been flying his drone around the South Bay for about a month. He created a website on which he regularly posts videos shot at police DUI checkpoints. He said he records officers to monitor abuses of power.
"My attorney told me there isn't really much regulation on them," said Saulmon, whose recordings are well known to South Bay officers. "I don't think it's a substitute for a hand-held camera but its definitely a complement."
Saulmon also has flown his drone over South Bay oil refineries and along the Hermosa Beach pier.
He doesn't see any privacy violations in his recordings.
But the presence of drones is causing a backlash.
"Once drones become widely used in our society, there's going to be a lot of concern," said Jennifer Lynch, a senior attorney with the Electronic Frontier Foundation, a San Francisco-based digital legal advocacy group. "It's because they're so in-your-face. It's easy to see the drone, it's easy to recognize the privacy implications."
At Hermosa Beach last year, an irate mother confronted a lifeguard about a drone that hovered near her and her daughter, and snapped photos while they were tanning.
In Connecticut, a man flying a drone over a beach was attacked by a woman who accused him of trying to take pictures of her.
And at Mt. Rushmore, a ranger confiscated a drone after it flew around the monument and over the heads of visitors.
In April, volunteers at Zion National Park in Utah watched a drone buzz over a herd of big horn sheep, separating the adults from the young.
"That's harassment," said National Park Service spokesman Jeffrey Olson. "Those are the kinds of things that have been going on."
The FAA said recreational drone use is generally permitted as long as pilots don't fly recklessly. Voluntary guidelines for model aircraft created in 1981 suggest flying at safe altitudes and distances away from airports, and avoiding crowds.
Police said there are some activities they consider illegal, including drones interfering with aviation activities. Using the planes to spy on neighbors would also raise red flags.
"I have to weigh it on a case by case basis," said Lt. Phil Smith, assistant commanding officer for the LAPD's air support division.
But most cases police deal with aren't sinister, often involving drones capturing beautiful scenery or historic moments like the Kings' Stanley Cup victory celebration.