Risk is costly in an abstract sense. Being in a risky situation makes you uncomfortable, which has costs in terms of your health. Risk can also have dollar values. Imagine you are carrying an expensive vase across a frozen pond. Reducing uncertainty often means doing more research.
Research costs time and money.
A ranch I once worked on had to shut down its dairy because it didn t pasteurize the milk, as required by law. Perfectly safe, damn tasty, and gone for the foreseeable future. In the National Forest system, equivalent things happen when whole areas are opened or closed to certain types of use, when in reality only small pockets within those areas deserve the regulatory action. Reducing uncertainty by getting more accurate data addresses this problem. Actually, we re trying to strike a balance between costs of reducing uncertainty and the costs of not reducing uncertainty.