Absolutely not defending anyone who drink drives but I think it's dangers to assume being charged with drink driving means he had a skinful (unless I've missed where the amount he drunk has been reported). Being over the limit can be as much as one drink it all depends on timings and your body mass etc.
I spent a summer working for National Express. Their drivers have to blow in to a Breathalyzer every time they start the engine. If they don't pass the engine doesn't start.
They also random breath test the office staff.