I think that you're broadening the question. Sure, sometimes you feel okay with code that's not at all tested. But surely you don't feel that code that is not

I think that you're broadening the question. Sure, sometimes you feel okay with code that's not at all tested. But surely you don't feel that code that is not at all tested is well tested. I'm talking about to what extent code coverage can and can not be used as a proxy for "well tested," not to what extent "well tested" can and can not be used as a proxy for "I feel good about my code."