DM and BRB, I'll ask you to respond to this again then:
And why would you, since you seem to be so hardcore about this, want to support a business that is diametrically opposed to your view?
I don't think the vast majority of those who post, especially the big corporations, really care that much. It is all about liability from the point of view of their insurance carrier, and not about guns.
Think about this: If a person with a gun shoots someone on your property, and you did nothing to prevent the person from having a gun, you are going to pay cash to the victims.
However, if you had a policy, and the shooter who was doing the shooting was breaking the law (robbing or spree shooting) well, then you tried to prevent the shooting, so you have a defense. After all, you put up a sign, had cameras, security lighting, etc. Since the law also says that a business can't be liable for the actions of a third party (a criminal) if they took steps to protect customers from the third party's action (sign, camera, lights), then you have created a situation where a business is liable for shootings that happen while allowing CCW and not liable for shootings that happen if they prohibit CCW, then the smart financial decision from the company's standpoint is to put up the sign.
Heck, if putting up a $5 sign that I know carries no legal weight, and looking the other way when people lawfully ignore the sign would save me from $1000 a year in liability insurance, I would do it,too.
This IMO is how the government uses lawyers and civil law to control things that they cannot Constitutionally control. They just make you liable for the behavior, while insulating you from liability for preventing the behavior.