Oneyedvic - your advice that to ask someone to drink soft drinks for seven hours would be 'almost criminal' underlines the heart of the drink-driving issue -
our culture has evolved into a belief that in order to have a good evening out, alcohol must be consumed, preferably beyond safe medical as well as legal limits. This will enable the imbiber to brag about his alcohol poisoning - which is what it is - next day by bragging with any number of adjectives - slaughtered - hammered - ratted - trolleyed - etc. ad nauseum.
Until we can disavow people of the notion that intoxication is a vital ingredient of an enjoyable social occasion, we will continue to have drink drivers.
How about "I'm driving so i won;t drink?" Is that so hard?
If you seriously need to be intoxicated in order to enjoy yourself, then you need to give yourself a maturity and personality check.
Be an adult - adopt some responsibility for your lifestyle, and if you have to go out and drink, and you can't or won;t make transport arrangements, then you deserve to be imprisoned and banned for the self-centred obnoxious uncaring drunken buffoon that you surely are.