"You Should Walk Home"?

There is a brief vignette in the uninspired movie Killers in which an inebriated guest is about to drive away after a wild party at the home of the film’s two leads, played by Katherine Heigl and Ashton Kutcher.?? The guest is obviously still drunk and Heigl’s character worries that he should not drive.? It’s puzzling that Kutcher’s character dismisses her concerns, saying something to the effect of “He’ll be alright.” (Mini-bleg:? was this a joke?)??But then Heigl calls out to the departing guest:? “You should walk home.”
Readers of?SuperFreakonomics will realize this is bad advice.? The book suggests that, on a per-mile basis, walking drunk is even more dangerous than driving drunk.? This doesn’t mean that Heigl should have advised the drunk to drive home – safer doesn’t mean safe.? She could have offered to call her guest a taxi or given him a ride home herself.
Here’s an example of a script writer’s attempt at a PSA possibly hurting people.