Among gentlemen, if you promise to not publicize it, you should follow your promise.
Also, if he was in no way convinced by the libs lobbying efforts over a meal, why would that be news. He probably has a lot of people that try to get him to change his mind. Must he discuss them all?
You assume Grahamnesty is more important than he is. I would think any discussion with him would be non-remarkable.
Why eat with them at all?