The problem I see with a personal breathalizer/starter is that you can falsify it, can you not? All one really need do is have someone else blow into it, and the engine starts, or am I missing some information (always possible!)?

Technology is wonderful, but even the most advanced can be foiled by the unscrupulous. What we need are more conscious and considerate inhabitants of planet earth, not more laws (or technology to inforce them).