Riding the Toronto subway is a reminder of the different kinds of watching that exist in the world. For instance, there is overt watching of the kind done by security cameras, guards, and other staff members. There is also both overt and covert watching going on between passengers: some trying to use a pointed stare to press someone to discontinue an unwanted activity, some trying to use an overt appearance of awareness to drive sketchy characters toward less responsive prey, some trying to examine their fellow passengers without making that fact obvious.
Overt watching is a tactic. When someone chooses to watch overtly, it is usually because they are in a position of authority and seeking to control the behaviour of the people they observe. By contrast, covert watching is a capability. Whether you are able to do it or not depends on the people and resources you have at your disposal – as well as whether your target has any interest and capability in conducting counter-surveillance. Misdirection can be used as an aid to both covert and overt watching. For instance, shops employ fake security cameras to scare off potential thieves. Meanwhile, people with headphones in but no music playing can be ideally placed to overhead conversations unobtrusively.
To a considerable extent, organizations like the police and the TTC are defined by the capabilities they maintain; their intentions can sometimes be discerned through the tactics they use.