No, there's an ethical way to do it. You get the permission of the top people in the project you want to test (in this case, that would be Linus and Greg K-H),

No, there's an ethical way to do it. You get the permission of the top people in the project you want to test (in this case, that would be Linus and Greg K-H), but the more junior maintainers aren't informed. You then see which bad changes are caught and which aren't, but you have a backstop to prevent malicious code from actually getting into a release. And even then, you leave it to the people in charge of the project to decide whether they think this would be a worthwhile test or a waste of time. To do otherwise is completely unethical experimentation on unwilling human subjects, plus a risk that if you "succeed" (in sneaking something by) you have harmed the public.