WIFI spoken here: chalk symbols point to wireless access. (Update).

What are those odd chalk signs suddenly springing up on walls and sidewalks around campus? If your school has a wireless network, you've probably been visited by War Chalkers--roving technophiles whose mission is to alert others that wireless access is nearby. It's the modern-day equivalent of hobo marks, a Depression-era secret language that told rail-riders that a particular house offered a hot meal or a place to sleep. According to FBI Special Agent Bill Shore, "Identifying the presence of a wireless network may not be a criminal violation. However, if the network is actually accessed, there may be criminal violations including theft of services; interception of communications; and misuse of computing resources, up to and including violations of the Federal Computer Fraud and Abuse Statute, Theft of Trade Secrets, and other federal violations."