>> Why bother with RFID tags, or badges? Simply register with your cell phone. We can then scan your Wi-Fi and Blue-Tooth signals when you approach the mic. >> >> -- Christian Huitema >> >> 'Simply' >> >> What is this simple technology of which you speak? I find that the best we can do with electronic systems is about 99% and that takes a huge amount of effort. I have a whole drawerful of bluetooth headsets and thats where they will stay because none of them works well enough to be useful. > > I am fairly sure Christian was being ironic. :-) I was. On the other hand, there are systems out there that will, for example, track customers as they move in a shop. They do that by listening to the Bluetooth radios. They definitely do not requests the customers to install an application or pair their devices. An extract form a research paper on the subject (http://www.gim-international.com/issues/articles/id1443-Bluetooth_Tracking.html) asserts that "Bluetooth tracking on the basis of MAC addresses does not violate privacy law. In fact, it simply makes use of a general Bluetooth function: scanning for nearby devices. Everyone is free to use this function, for instance when turning on a mobile phone in a public place." So it must be just fine. -- Christian Huitema