Another note on those carb blockers. They will only block a certain amount of complex carbs and they do not block sugar at all. So don't think you can take them and scarf down a couple of candy bars and get away with it diet-wise. It won't work.
In the same line of reasoning from the Karate Kid quote, "Best defense is not be there", the best way to block carbs you don't want is to not put them in your mouth to begin with.