"As part of the CamperForce program, Amazon hires workers on temporary contracts from early October until December 23, paying them near minimum wage while covering the expenses of staying in an RV park.
The company targets older workers, who they believe have a stronger work ethic than their younger counterparts."
The program has been around since 2008. Apparently Amazon does not work them as hard as regular hires, as they only need to hit 70% output (in items per hour) of year-round employees.
[1] https://www.wsws.org/en/articles/2017/11/06/camp-n06.html