WASHINGTON — Kevin Good thought there was an 80 percent chance he could deliver his brother’s wedding rings with a tiny drone.
‘‘The other 20 percent is that it could go crashing into the bride’s mother’s face,’’ the Bethesda cinematographer somewhat jokingly told his brother.
His brother was OK with those odds, so he signed off.
A few weeks ago, sitting in the back row at the ceremony near San Francisco, Good steered the drone to the altar, delivering the payload in front of 100 or so astonished guests. His brother grabbed the rings, then watched as Good buzzed the drone off into the blue sky.
‘‘At the end of the wedding, that was what everyone was talking about,’’ Good said. ‘‘It was pretty awesome.’’
This is the gee-whiz side of drones, a technology typically associated with surprise air assaults on terrorists. Drones designed to do the bidding of ordinary people can be bought online for $300 or less.
They are often no larger than hubcaps, with tiny propellers that buzz the devices hundreds of feet into the air. But these flying machines are much more sophisticated than your average remote-controlled airplane: They can fly autonomously, find locations via GPS, return home with the push of a button, and carry high-definition cameras to record flight.
Besides wedding stunts, personal drones have been used for all kinds of high-minded purposes — helping farmers map their crops, monitoring wildfires in remote areas, locating poachers in Africa. One local drone user is recording his son’s athletic prowess from a bird’s-eye view, for recruiting videos. But not every flier is virtuous.
There are videos on YouTube of people arming drones with paintball guns. In one video — apparently a well-done hoax to promote a new video game — a man appears to fire a machine gun attached to a small drone and steer the device into an abandoned car to blow it up.
Privacy and civil rights activists worry about neighbors spying on each other and law enforcement agencies’ use of drones for surveillance or, potentially, to pepper-spray protesters.
“Drones make it possible to invade privacy without even trespassing,” said Amie Stepanovich, a surveillance expert at the Electronic Privacy Information Center.
But already, several law enforcement agencies across the country, including the Queen Anne’s County sheriff’s office on Maryland’s Eastern Shore, have purchased the devices.
Meanwhile, as many as 40 states, including Maryland, have considered legislation to limit police drone use or ban the devices. A Colorado town is weighing an ordinance to allow hunters to shoot down drones.
Drone defenders, including the Association for Unmanned Vehicle Systems International, say those fears are overblown and threaten the potential economic benefits of commercial drones. The group predicts 70,000 new US jobs and a nearly $14 billion economic boost.