In a particular state, read the law carefully, including the case law. Here in FL, the alcohol prohibition covers only the bar area of the restaurant.
This is another example of an area in the CCW laws which needs "cleaning up." It's something that looks good on paper, but can be a problem. Most experienced cops know very well what they are looking at in a situation, and wouldn't bother anyone who isn't making trouble. All you need is one prick, or a new one out to make a name, and you have trouble.
In TX, for example, the law defines an alcohol establishment as one which derives more than 50% of its revenue from the sale of alcohol. In FL, the law is "more than half." On paper, they say the same thing. Depending on the spin at a trial, I suspect a tight ass could make a better case against you with "here are the numbers" than in the other.
The clean-up I'd suggest would involve a better definition, probably codifying (as opposed to case-precedent) the over half part, and possibly adding a demonstrable intent, such as sitting at the bar rather than just walking through (to go to the bathroom). Another area is large stores which want to prohibit carry. It's a public accommodation. If I'm complying with the law, leave me alone! This private property business is fine for an individual, but not a public accommodation - think what teh reactions would be in any other context than guns. <rant over>