"Amazon uses the scanners to measure and record each worker’s productivity in terms of work units completed per hour,"
No, behaving like that you do not have workers you have robots.
Amazon's management has decided that in order to maximise profit you have to reduce any human being unfortunate to be employed by the company to the status of a faceless, inconsequential machine without feeling, needs or indeed a life outside the confines of the hive.
More like worker ants than people and just as disposable.
I will not do business with such an appalling travesty of "free enterprise" and I urge everyone to consider the means with which Amazon delivers the goods you buy from them.