One of the difficulties in using NITs in surveillance is that computers (so far) are not very good at exercising the kind of judgment necessary for interpreting data. They can gather, sort, and process information very effectively, but they can only make “decisions” according to specifically programmed variables.
Face recognition is one example.
Recognizing faces is a difficult task even for humans. But although there are many instances when it would be useful for us to have computers that help us identify someone by examining his or her face, so far this has not been successful.