I don't think it's illegal, just doing so opens you up to legal challenges from the person. And you may be 100% provably correct, but no one wants to go throug

I don't think it's illegal, just doing so opens you up to legal challenges from the person. And you may be 100% provably correct, but no one wants to go through the legal wranglings to deal with it, so the typical corporate response is to just provide the quantifiable facts - dates of employment.