In such projects there is often a promised release date and a contract stipulating e.g. a total test pass rate of at least, say, 95% or something like that. No

In such projects there is often a promised release date and a contract stipulating e.g. a total test pass rate of at least, say, 95% or something like that. Now if you use a fuzzer to generate a lot of test cases that fail (if it only saves the failing ones) it will impair the ability to release. So sadly there are often incentives to not fuzz close to a release. The management euphemism is “taking a risk based testing approach”, when selectively removing test cases to make the numbers to qualify for a release.