While I agree with the rest of your points, I have to pull you up here. This is the reason they can't charge you based solely on your first roadside meeting. They have to do a second reading (some time later - 15 mins or half an hour or something), I think with a more accurate meter, to be able to charge you. Any reading from mouthwash, cough syrup etc would be gone in this time. And any foods that have enough alcohol content to keep you above 0 for a significant amount of time well, you shouldn't be eating them and driving. Alcohol has the same effect on your mind/body regardless of if you drink it or eat it.
But yes, other than that I agree with you 100%