True and largely accepted as rational even for things such as life insurance (suicide and death in "high risk" activities e.g. skydiving, piloting experimental aircraft, etc. often excluded).

When it comes to health insurance, though, people seem to have this unreasonable expectation that they should be allowed to be obese, not exercise, and have a poor diet, and then have their diabetes, kidney failure, and heart disease fully paid for while paying the same rates as everyone else, or even paying no premium at all (e.g. government provided health insurance).