The underscore is the annotation

I understand that; the problem is that it makes it so easy to bypass the safety net the warning is intended to provide. For example, not logging an exception; You'd have to be really intentional to block the warning with an actual annotation, but using an underscore would be so easy you'd just fall into a pattern of always commenting those out. It's better to have a line of code screaming "I'm doing something that looks wrong here but really it's okay" instead of "_".