and for that awful moment when you can't get through to ATC due to frequency congestion? what do you do then? You safely navigate the plane away from terrain and the most likely way to do it is using the published missed.
That would be using emergency authority, which is fine but may result in some unwanted dialogue with the FAA after the fact.
The first "rule" is to not accept a visual approach in weather conditions that are marginal for your aircraft.