The key here is just as you said, "I won't". Why not? Because if I did it would defy god's perfect knowledge. Once you realize that...you'd have to realize that at that moment of "choosing" I cannot actually choose the Pepsi and prove god wrong. I have only one course of action (its no longer a choice, indeed it never was). No matter if it appears or feels as if I made a choice, it wouldn't be. Instead, life would become a series of events that simply give the illusion of free will and some sense of control.
Needless to say, this would put the entire Christian religion in jeopardy. What would be the point of judging a man's life based upon his actions, his choices, if he never had control over those actions and choices to begin with?
Take a few steps back to look at the larger picture and it makes even less sense. Why would god create the universe if he already knew the results of this action? Why create mankind, judge their actions, and then eternally reward or punish them? Would it not be simpler to place the souls of those going to heaven in heaven, and the souls of those going to hell in hell? He could skip the entire "life on earth" aspect of this game and send everyone immediately to their reward or punishment...and the results would be exactly the same. Indeed, if "heaven" and "hell" are not actual places that exist within the universe and instead exist apart from it...why create the universe at all?
A god who knows the future conceptually ruins the entire point of the Christian religion.