More unintended consequences
Risk management is harder than it looks, in part because of the unintended consequences of approaches to mitigate risks. Some studies have suggested that wearing seat belts actually increases fatalities, for example, because some people drive more recklessly when they wear seat belts. I just came across another example of this, and this has to do with the labeling of alcoholic drinks in Australia.
In Australia, there are apparently laws that require alcoholic drinks to be labelled so that you can tell exactly how much alcohol you're getting when you drink one. The intent is to help people drink responsibly and safely, but it seems that younger drinkers have found another use for this labelling, and that's to help them optimize how much alcohol they get so that they can get drunk in the shortest possible time. This is discussed in "The impact of more visible standard drink labelling on youth alcohol consumption: Helping young people drink (ir)responsibly?," by Sandra Jones and Parri Gregory, which was published in the January 2009 issue of Drug and Alcohol Review.
That's the sort of risk-risk tradeoff that makes risk management harder than it looks.