schwit1 asks "How can I automatically have my wi-fi turn off when I leave the house unless I specifically turn it back on?" and provides this excerpt from Wired to illustrate why that would be useful: "Hundreds of thousands of pedestrians walking past 12 locations unknowingly had the unique MAC address of their smartphones recorded by Renew London. Data including the "movement, type, direction, and speed of unique devices" was recorded from smartphones that had their Wi-Fi on. First reported by Quartz, the data gathering appears to be a Minority Report-esque proof-of-concept project, demonstrating the possibility for targeted personal advertising. 'It provides an unparalleled insight into the past behavior of unique devices — entry/exit points, dwell times, places of work, places of interest, and affinity to other devices — and should provide a compelling reach data base for predictive analytics (likely places to eat, drink, personal habits etc.),' reads a blog post on the company's site. In tests running between 21-24 May and 2-9 June, over 4 million events were captured, with over 530,000 unique devices captured. Further testing is taking place at sites including Liverpool Street Station."
(The name sounds a bit like a government project, but Renew London is actually an advertising / marketing firm.)