But what if the person sharing lunch with God decides beforehand to choose something different to whatever God says they will choose? Would God know that and say “You’re going to choose something different to whatever I say you’re going to have.”?
I think the question by the original poster gets to the heart of the nature of time and the concept of predestination. If we truly have free will, then the future cannot be predestined, and so perhaps God could not ‘know’ what we are going to choose.
Or perhaps God does ‘know’ all of the ‘free will’ choices that we’re going to make. But if, as in the suggested scenario, God provides any knowledge of future events to us in the present, then it messes things up.