Which is weird to me. Why is a company expected to be onmicient about their employees? Do we have to do psych evals on everyone to make sure they might not do s

Which is weird to me. Why is a company expected to be onmicient about their employees? Do we have to do psych evals on everyone to make sure they might not do something that the company could be liable for? Why isn't law good enough here? If Subway wasn't involved, isn't the law sufficient? Eg, a person committed a crime, Subway wasn't involved. Do you disagree?