I understand this better than you can possibly realize.
HOWEVER...can you show me any evidence than a firearm in a car is an increased safety or health risk to the work force?
I can't quantify this right now, but I'll bet there are more lost workdays due to people 'toughing out' colds and flu than there are from firearm related incidents amongst co workers.
So is it really about the safety and well being of their employees?
You can't be serious. As others have pointed out, a firearm
on the premises (including a locked vehicle but available to the owner) is a risk to others when that owner is involved in disputes, including with the employer. I recall
the shootings in Sunnyvale (Silicon Valley), at DEC in
Hudson Mass, the various incidents at post offices (genesis
of the "going postal" syndrome)..
My wife carries out terminations as part of her job. Its
stressful enough without the danger of a fired employee coming into mahogany row and offing the management. Ultimately this issue will lose on the grounds of common sense and liability.