4) placing a magnet on the side of the camera (does this work?)

Not with CCD cameras. All the other methods you mentioned require special physical access-- it won't work if one gets photographed while placing post-its on the camera window... The high error rates of image recognition make this whole scenario a future issue. One FAA funded experiment used mice to detect excessive adeneline (the mice go nuts or their heart rates increase just by smelling the excitement); the idea was to catch hijackers who would generally be a bit excited. This sounds obvious boneheaded because of all the people who fear flying...but the stated reason for abandoning the research was that mice don't rate too well as anonymous tipsters! Anyway, the error rate was very high too. However, the whole "profile" thing used by the WoD is essentially a conscious application of generalization that neural networks do. This may expand if "suspicion detection" is socially acceptable--my guess is that it would not be accepted given the speeding ticket automation systems that have been widely rejected (they probably could have gotten it accepted if the reduced a speeding ticket cost by a magnitude and considered it like a parking ticket--but these are legal changes, not technological changes, so they are much more difficult to do). The OCR of cash serial numbers would be highly probabilistic--that is, too many transactions would not be tracked so the knowledge of the flow would be partial. More likely would be that all large cash deposits would be scanned for general analysis just as large cash transactions require that a bank fill out a special form and send to the State. Paul E. Baclace peb@procase.com