I bolded a particular part above - if the crossing was that close (6") It's a safe bet that starboard doesn't consider that "clean". I wouldn't if it were me. Starboard is obligated to avoid collision and would be reasonably expected to start changing course to avoid that potential collision. There is judgement involved. As a starboard boat, I'm probably bearing away a little toward the end of cross that's only clear by 6" to make sure we don't hit if some other variable comes into play. At that point, I have been fouled and I will make a decision, as the starboard boat, whether or not to cry foul. I don't expect port to do turns unless I indicate foul. I don't expect port to really know if he fouled me unless I indicate foul. I would expect no different as the port boat. If they ended up in the room with a crossing that close, I would expect starboard to win the protest. Starboard has to react in a reasonable manner to avoid contact...so even if you could put a tape measure and video camera on it to demonstrate that you would have been clear by 6", it may not be enough to win the protest.