The real issue here is the state law and what it says and requires of the CCer AND the business. In SC and I am sure elsewhere the business is required to post a specific sign with a specific size and specific notification and graphics--if this is not done, you certainly can walk into a business CC--being CC, even if the business owner or manager is anti-firearm, it will make no difference since he will never see the firearm. Should, for some reason, it becomes obvious and he asks you to leave, you should leave, but only on a direct comment from management--the fact that you are in the store and are CC is not illegal since the signage was not there or incorrect in the first place. If your state allows CC with no restrictions on a business and/or the signage is incorrect, but also does not allow OC, you are breaking the law being OC in the business or not.
Personally this a "haha" thread (I do not like using the "D" word) sounds like a yada yada.