Recently two people have been cautioned in the U.K. for piggy-backing on wireless internet networks, Reuters reports:
On Saturday, a man was arrested after neighbours spotted him sitting in a car outside a home in Redditch, Worcestershire, using a laptop computer to browse the Internet.
A 29-year-old woman was also arrested in a car in a similar incident in the same area last month.
Both received an official caution, a formal warning one step short of prosecution, for "dishonestly obtaining electronic communications services with intent to avoid payment".
They were among the first to be arrested for piggy-backing in Britain. Gregory Straszkiewicz, from west London, was the first person to be convicted of the offence in 2005. He was fined 500 pounds and given a 12-month conditional discharge.
This type of incidents can easily be prevented by securing your wireless network with a WPA key.