Remember the Mahmoud al-Mabhouh assassination last January? The police identified 30 suspects, but haven't been able to find any of them.
Police spent about 10,000 hours poring over footage from some 1,500 security cameras around Dubai. Using face-recognition software, electronic-payment records, receipts and interviews with taxi drivers and hotel staff, they put together a list of suspects and publicized it.
Seems ubiquitous electronic surveillance is no match for a sufficiently advanced adversary....
(if it doesn't work, don't fix it - get rid of it! -fc)