Because it is possible to intervene at any moment and because the constant pressure acts even before the offences, mistakes or crimes have been committed. Because, in these conditions, its strength is that it never intervenes, it is exercised spontaneously and without noise,
This is very familiar to relation to the Evil eye, the all seeing eye. Follows you everywhere, watches you constantly yet you are hardly ever aware of its presence. This is comparable to to the roll of our government tracking us through the little camera in our computers, following our car gps', tracking our back accounts...panopticism has not diminished but evolved