The first worker tracking systems, using crude scanners were introduced in the 1970s. Such systems, for example featured (Larson., The Naked Consumer, p. 133)
"programmed computers to watch for subtle diversions from normal sales patterns at each checkout lane - having found that by the end of each day the pattern of sales from any one lane should mirror the pattern of other, comparable lanes. Any major departure is flagged as an 'exception log
And, of course, after a certain number of exception logs' - the worker is questioned about his -her habits.