An old neighbor of mine was a headhunter. He once told me that some companies had a trick to get around the law. Upon getting hired, you'd sign a document saying that you'd agree to all policies in the employee handbook. Pretty standard stuff. One of the company policies was that you needed to prove any previous salary you stated in the negotiation. If it was too far off, they'd just terminate you. The trick is that they didn't ask at all during the hiring process; you're already hired and onboarded and then HR puts a meeting on your calendar to explain the policy to you.