As a pedant, it sometimes makes me uncomfortable to make these decisions "quietly".
While I wholeheartedly agree that this is an important skill for all developers, it begs the question: Why should the dev be responsible for deciding when an issue needs to be brought up? Why should the dev be making these quiet decisions, is this not evidence of incomplete requirements?
There should be protocol here instead of relying on the dev's subjective sense and opinion.
Generally speaking, I feel like this goes outside the bounds of the developer's responsibility. Not every dev has honed this skill; it could be dangerous. I would choose to err on the side of caution and apply your rule of thumb above in almost all situations.