Many business owners would say yes. That the quality of one's credit shows the quality of one's character. This, in my opinion, is no different, than in the olden days, when companies used to control entire towns and would monitor their personal activity from church attendance to their children's grades. Its a form of paternalism, which our modern workforce typically resents and for good reason.
However, this form of credit paternalism is even worse. At least in the company towns, they provided church, schools, etc for the working class; therefore actively trying to promote the behaviors they were looking for. In the case of good credit, the company has had no role in your relative feast or famine prior to your coming to work for them, so they should have no role in judging your credit situation.
At the very least, even if that doesn't tread water, I would think that there is an argument that it is an invasion of privacy.