Legality of piggybacking

Laws regarding "unauthorized access of a computer network" exist in many legal codes, though the wording and meaning differ from one to the next. However, the interpretation of terms like "access" and "authorization" is not clear, and there is no general agreement on whether piggybacking (intentional access of an open Wi-Fi network without harmful intent) falls under this classification. Some jurisdictions prohibit it, some permit it, and others are not well-defined.

For example, a common but untested argument is that the 802.11 and DHCP protocols operate on behalf of the owner, implicitly requesting permission to access the network, which the wireless router then authorizes. (This would not apply if the user has other reason to know that their use is unauthorized, such as a written or unwritten notice.)

In addition to laws against unauthorized access on the user side, there are the issues of breach of contract with the Internet service provider on the network owner's side. Many terms of service prohibit bandwidth sharing with others, though others allow it. The Electronic Frontier Foundation maintains a list of ISPs that allow sharing of the Wi-Fi signal.

Singapore
In November 2006, the 17 year old Garyl Tan Jia Luo, was arrested for tapping into his neighbour's wireless Internet connection. He faced up to three years' imprisonment and a fine under the Computer Misuse Act. On 19 December, Tan pleaded guilty to the charge, and on 16 January 2007 he became the first person in Singapore to be convicted of the offense. He was sentenced by the Community Court to 18 months' probation, half of which was to be served at a boys' home. For the remaining nine months, he had to stay indoors from 10:00 pm to 6:00 am. He was also sentenced to 80 hours of community service and banned from using the Internet for 18 months; his parents risked forfeiting a S$5,000 bond if he failed to abide by the ban. Tan was also given the option of enlisting early for National Service. If he did so, he would not have to serve whatever remained of his sentence.

On 4 January 2007, Lin Zhenghuang was charged for using his neighbour's unsecured wireless network to post a bomb hoax online. In July 2005, Lin had posted a message entitled "Breaking News – Toa Payoh Hit by Bomb Attacks" on a forum managed by HardwareZone. Alarmed by the message, a user reported it to the authorities through the Government of Singapore's eCitizen website. Lin faced an additional 60 charges for having used his notebook computer to repeatedly access the wireless networks of nine people in his neighborhood. Lin pleaded guilty to one charge under the Telecommunications Act and another nine under the Computer Misuse Act on 31 January. He apologised for his actions, claiming he had acted out of "stupidness" and not due to any "malicious or evil intent". On 7 February he was sentenced by District Judge Francis Tseng to three months' jail and a S$4,000 fine. The judge also set sentencing guidelines for future 'mooching' cases, stating that offenders would be liable to fines and not to imprisonment unless offences were "committed in order to facilitate the commission of or to avoid detection for some more serious offence", as it was in Lin's case.