There's always the "fine print". Most companies that the employees drive their own vehicles to work have a clause that usually states "No firearms on company property". Of course the parking lot falls under that jurisdiction.
I'm sure they are looking at it from the employees going ""postal"" and shooting up the office / staff, and not seeing the benefits of law abiding citizens and their right to protect themselves and others.
Look around, the world is full of liability. Companies and Corporations know how to play the game, even if you get hurt at work they have a loophole or two set aside. Our company has weekly safety topics that never get properely covered, they just read a few high points and then we all get to sign that we "understood" the topic. So now if you fall off a ladder or scaffold, the company can't be sued for anything because you signed the sheet. Their position is that they trained you and you still had an accident, they shouldn't be liable and they have the paperwork to back it up. It's not about protecting you the employee anymore, it's all about covering their corporate a$$es and limiting the liability losses.
That being said, I still stand by the "out of sight - out of mind" statement and would have one if not several within reach (but out of direct sight) in my vehicle regardless of company policies.
It's a new oxymoron: It's illegal to bring your legally permitted weapon to work?
