A man has been arrested and charged for riding someone's home Wi-Fi network.

Benjamin Smith III, 40, was arrested on April 21 outside the home of a Richard Dinon and charged under a Florida law that prohibits unauthorised access to a computer or network. A pre-trial hearing is scheduled for Monday.

Dinon saw Smith sitting in a parked car in front of his house with a laptop. "What made him suspicious was, every time he looked toward the car, the guy closed the lid on his laptop," said a police spokesman. So Dinon called the police and when they turned up, Smith closed the computer.

The police asked him what he was doing and he admitted to using Dinon home wireless network. Smith was arrested, and the laptop seized and sent off for investigation.

Dinon said he was worried that Smith might be doing something illegal or inappropriate. "What he was concerned about was not so much that the guy was accessing his [network], what he was concerned about was what he was accessing," the police spokesman said. Dinon was afraid he might be linked to whatever Smith was doing because it was his LAN being used, he said. "This guy did not want himself to be identified as accessing porn sites or child pornography."

The state law under which Smith was charged prohibits accessing a computer or network knowingly, willfully and without authorisation. The police said it's the first time anyone has been arrested for using someone else's Wi-Fi.

But Gartner analyst Ken Dulaney has no sympathy for Dinon and managed to inject some commonsense in the situation. "He should have put security on his wireless LAN system. It's the guy's fault that he left it open," he said. "Don't the police have anything better to do?"

Open wireless LANs are still common in many residential areas even though Wi-Fi routers can be set not to broadcast their names and tools for encryption have improved since the early days of the technology. Dulaney estimated that half of all wireless LANs are completely open to unauthorised users.