It is hard to tell whether it always is. If they are smart they use a deterrent, which must be visible to work, to decrease the number of potential targets to track, and something well hidden to follow the remaining real/potential troublemakers.
It is hard to tell whether it always is. If they are smart they use a deterrent, which must be visible to work, to decrease the number of potential targets to track, and something well hidden to follow the remaining real/potential troublemakers.