Amazon, $5k, and the Great American Warehouse

So it's all over the news today that Amazon has a (new?) policy to offer its warehouse workers up to $5,000 if they agree to quit the company.

But my impression was that Amazon's warehouses were primarily staffed by contract workers from staffing companies -- as in the scandal about their overheated Pennsylvania warehouse a year or so back. And the stories from that end certainly made it sound like Amazon carefully increases the workload on its warehouse staff so that most or all of them can't actually fulfill their piecework goals, and so Amazon can get rid of them before their hourly wages get too high.

Has any actual reporter gotten her teeth into this story yet? I know the Pay to Quit policy came from Zappos, which, while part of Amazon now, has a different, higher-priced focus and so presumably more money to spend on retention. But this policy is for Amazon's warehouse jobs, which are tough and physically demanding at the best of times, with fairly low pay as well.

Or, to look at it from another side: if I owned substantial Amazon stock, and was still waiting (since 1995) for them to start using their near-monopoly power to begin throwing off cash, I would be really annoyed that they were using that money instead to bribe their employees to go work for someone else.