Aside from the obvious issue of the system giving false positives and causing an accident, Toyota could be putting themselves in a slippery slope when it comes to possible legal issues. What they are technically doing is involving themselves in the "enforcement" of the drink-driving laws - surely meaning that one day when their system fails to prevent a heavily inebriated person from driving one of their vehicles and subsequently being involved in a collision, then thanks to our out-of-control blame culture they would be wide open to a barrage of litigation, regardless of where the true blame should be placed?