Actually Fistful, you CANNOT keep someone from your business or employment due to any of the reasons that you mentioned (color, race, age, etc..), it's federal law that you cannot discriminate on certain factors.
You are able to do so in your home, you have those Rights while a business or a place of employment does not.
Since gun ownership is not a protected aspect, a business can bar you from their property as a policy of employment if you insist on carrying a gun and/or weapon on their property while they cannot bar a non-employee (unless marked by state law or federal law (federal buildings/property)) that has a permit from that property or business. Example, here in Oregon, only certain places are marked by state law (and federal buildings by federal law) and no other place can bar you from their property. The hospital in Eugene is marked "no weapons" with the gun sign with a slash through the circle but it means nothing, it's just a symbol of their anti-gunness and it carries about as much weight as a vacuum (not the cleaner, like the vacuum of space, nothingness).
I choose to carry at work. Yes, it's against the "rules" but I would rather have the strain of finding another job then the stress to my family of having to make my burial arrangements. I know the policy, as do all the employees here, but let me tell you, I'm not the only one that has a gun on trust property.
As for the dogs, heck, they would go crazy on my car. I bought it new in 1992 and though these years I have spilled hoppes in it, still finding loose ammo and brass, have had oil soak into the carpet in the back, have spilled powder (when shooting the BP's), etc.. Even if they never found a gun (which they wouldn't since it's in my "hide a way" case that is attached to me) they would still fire me for "cause" (they will think that I just have it very well hidden in the vehicle).
Reminds me of the time I was picked to have a randam search when I was active duty at the gate. Dog went wild (explosives dog) and they did an "in-depth" search, found nothing but some spilled powder and the oil stain.
Wayne