This is an interesting topic, and one that can (and does) easily fall into the "us" vs. "them" category, something which only serves to increase anger on both sides of the issue. While I agree that we should be letting businesses know that they lose income by posting "no weapons" on their business, a totally confrontational approach will ultimately be self-defeating. It is also the same tactic being used by anti-gun groups.
As far as the open/concealed carry issue goes, I am not sure that pushing the open carry issue is strategically beneficial for firearms owners at this time. Open carry, especially when approached in a confrontational manner, lowers the proponent of firearms ownership to the level of those misinformed anti-gun citizens (yes, citizens - because I refuse to lower myself to their level by demonizing them the way they demonize us). There are too many people who have been fed misinformation about how responsible firearm owners can be expected to behave in public for such a tactic to work. What is called for here is not confrontation, but education, and this should be the first strategy deployed in these types of situations. Only when the business community and the public recognizes the responsibility with which the majority of legal firearms owners behave can we expect to have reasonable reactions from people who encounter open carry situations.
From what I have seen, many of these policies are knee-jerk reactions by companies who are misinformed about how concealed carry works. I think that, instead of being confrontational (especially in an angry manner), an inclusive approach would benefit gun rights more. How about approaching the local managers and assistant managers with an offer of free concealed-carry and/or gun safety classes? They could then have a better idea of how and why we chose to exercise our rights to self-defense, and be informed about the type of training that concealed carry permit holders have in regard to when and how to use our firearms legally and safely. Of course, it also allows them to shoot in a safe and instructive environment, which in my experience does more for people's understanding of firearms than anything else.
I realize that the reality is that many of these businesses are national chains, and I believe that a national organization - say the GOA or NRA - should make these same offers to the upper administrative levels of the national chains, but as a local organization we can instill confidence in local business owners that we are responsible and trained. Additionally, we should look at other people - politicians, representatives, etc. - who we can invite to participate in such classes. Such things will only serve to inform against, rather than rant against, anti-gun rhetoric.
Is there a form letter that can be sent to some of these businesses expressing concern over carry policies? If not, why not? A reasoned, respectful, and considered letter to these businesses expressing support for our right to carry and, more importantly, their right to freely express their rights however they see fit, might be a good start to a good-will, informational campaign.
Anyway, that's my 2 cents - or $1.50, the way I went on...