My employer has a similar policy, but unbeknowenst to me. I had a rifle in the rear window of my pickup for at least the first year I worked there, until a coworker made me aware of the policy, then I just mounted the racks behind the seat. out of site, out of mind,right? I doubt they would search here and especially now, because of various hunting seasons, would have to send over half the people home, and we are behind on product the way it is.
Your place may be more strict, as stated above, the risk is your to take, or not to take.