Several former Amazon workers in Kansas and Tennessee said they had vague memories of signing a non-compete clause, but hadn`t given it much thought. Two workers who left amazon`s storage jobs in 2012 and 2013 said they had no recollection of signing a non-compete clause. It`s unclear when Amazon began getting warehouse workers to sign that deal, and the company hasn`t responded to Questions from The Verge about it. Two other Amazon employees, approached by The Verge, cited the confidentiality agreement they had signed with the company by refusing to share their experience for this story. Signing non-compete clauses is more common in states that are more prone to enforcing treaties, according to preliminary results from a study conducted by scientists at the University of Illinois at Urbana Champaign and the University of Michigan. . . .