Drunken drivers - technological solution?

As current campaigns don't convey the message clearly enough to the idiots themselves and because some of their friends should be considered brain dead for allowing them to drive, I have been pondering about possible preventive measures for the last decade or so.
 Maybe it's me but some solutions I came up with wouldn't look all that weird in a masochistic dungeon and this would be the exact reason why car manufacturers would pass for the occasion.

I believe that no solution should depend on the human(s) that are in whatever way involved in the drinking party so this excludes obviously the party goers but also the bar tenders, bouncers...  Humans are never to be trusted as their behavior is unpredictable, their thinking is subjective and their mind is - even in drunken status - way too creative:
- any type of breath test linked to the car's ignition system: there will always be an even bigger idiot that will do the test for the drunken moron.
- any type of behavior-aware car control that will stop the car if the driver is swaying: this system will have an on/off switch as car manufacturers (or car dealers) cannot be trusted to take a stance here.
- any type of 'social control' by either friends or a team to talk sense into the drunken idiots ... don't have to explain this one.
- police check points.  Since when do THEY know where the good parties are at?  The police force is massively outnumbered by the amount of idiots not included in their ranks.

So basically most solutions will fail in some way unless the validation process is strictly scientific and not invade the driving of sober drivers using the same vehicle (again, it should NOT have an on/off switch).

Being a designer rather that a scientist, the only solution I found that works - until I find a way to cheat it - depends on nanotechnology and has been tried some 2000 years ago in a small village called Cana in Gallilee near Nazareth.  Actually the test in Cana was run inverse.
Consider the complex chemical structure of wine as a mixture of 'stuff' with alcohol (or whatever scientists call the stuff that intoxicates us).  Consider us humans as the type of mammals that will not hold any liquor without our body showing 'some' chemical reaction to it (via glands...).
If nanotechnology could be used to non-intrusively add some nano-drones to any beverage without harming us, one such drone could be designed to stay afloat so it will reach the lips/tongue/mouth quickly, the following process could be triggered:
- person sips from the drink
- nano drone touches lips and analyzes the saliva to check if the person is drunk
- if sober: no problem, drone gets consumed and starts his route through the body.
- if alcohol-reaction is detected: drone could trigger different types of effects (change taste sensation, provide small electro shock...) but the one reaction I envision is isolate the alcohol element chemically from the rest by changing the beverage's molecular structure to e.g. water.

I know this sounds far fetched but it is less science fiction that you think.  Anyhow, if Jesus could turn water into wine 'just like that' (yes, I know he had a friend in high places and perhaps some super powers) maybe this day and age we should be thinking about inverting the process.