Read this, http://butlerpappas.com/1411.
Many court decisions have upheld that a business has "No Duty to Protect" it's patrons. I also would like to remind you that LE has no duty to protect you from crime either.
Since there is no requirement for you to go to that place, you can't really argue that you were forced to be disarmed and helpless.
A business can make that call. Up to them. Their private building, their choice.
Now, I must admit in cases where you HAVE to go there (for example, some state buildings such as the DMV) I think that if they
make you go there but don't allow you to defend yourself, then indeed they SHOULD be forced to assume responsibility for your protection. After all, they are forcing you to be comparatively defenseless. Against, for example, our state constitution.
But again, for places like Panera---it is a private building, and you don't have to go there. If you choose to do so, it is no different than if the business says "no shoes, no shirt, no service," yes? You need to match their entrance requirements.
Which is why, I'll note, that I don't go to private businesses that don't allow concealed carry. As for Panera----they are making the smart business choice of keeping a vocal group happy while allowing everyone to do pretty much exactly what they were doing before. Am I thrilled about their choice? No, I'd rather have them vocally support legal gun owners. Am I surprised at their choice? Not at all.
After all, their business is food, not politics, and they want to sell lots of food to everyone.
I note: while I personally am not interested in open carry, and I think most of the attention-seeking open carry folks we've seen in the news lately are idiots, that doesn't change the fact that I'm not thrilled that businesses are now asking people who open carry to please not do so. (I'll note that "attention-seeking open carry folks we've seen in the news lately" is not a category that includes all open-carry folks.)
But private businesses have the
right to make their own choices about what they allow in or not. Not going to go out of my way to give them money for their choice---but I certainly respect their right to MAKE that choice.