It's a sad thing - but that kind of stuff also happens in non-drinking and driving situations.
It's ultimately playing the emotional argument on why you should not drink and drive. This works I guess, humans are emotional and can be somewhat illogical.
You should not drink and drive because
1. You dont want to take responsibility for someone else's life. When you get behind the wheel you do that.
2. Prohibition groups such as MADD have made it a living fucking hell if you get caught.
3. DUI's with injuries in CA can get you 10 years in Prison
4. You will be sorrily inconvenienced if you lose your license
5. Call a fucken cab.