Without wishing to deflect the central argument..... if the reading reported in yesterday's Guardian was correct (about 25% over the UK drink/Drive limit) - I, personally, would be more concerned at her lack of rest than her alcohol level.
I know how I feel after the equivalent of four units of alcohol and I know how I feel after less than 3 hours sleep. In my opinion the lack of sleep is by far the more serious threat to safety.