TexasCHLforum.com

It seems that such a rule is an attempt to limit liability, so the company can say, "Well, we told them not to...so we can't be held at fault."

Regarding how to protect yourself getting to work and back home, the typical organizational response would be something like, "That is of no concern to our stockholders/board of directors/etc." or "The employee should not take the law into their own hands. The employee should call the police."

Either way, it seems the effort is to protect the company bank accounts - "follow the money" is a good guide to understanding motivations.