Red over Red - Not Under Command (NUC) Lights

[capngeo]

I am hardly in the turn them all on crowd; I despise them as much as you do. I have way too many days at sea to be foolish enough to be lumped in with the credit card captains. Similarly, I do not parade around the yacht club in topsiders, a captain's hat, and shirts with alligators whilst hoisting signal flags and debating minutiae of the rules.

My background is in working vessels, and as a demographic, I am sure that group is more compliant with signals than any group of pleasure boaters. That said, I will say again that given the circumstance set forth by the OP, an anchor light would be the best light to display.

In rebuttal to your assertion that sea anchored vessels are underway, I submit that even a vessel anchored to the bottom moves somewhat.... It that vessel underway as well? By your inference only a vessel aground would not be underway and could display an anchor light

ETA: Once upon a time, I was pushing two head barges, 110' long, each loaded with 3700 tons of concrete bridge beams. In a crossing situation at a harbor entrance some yachtie tried to invoke the "I'm a sailboat and you need to give way" ( the fact that i was towing, CBD, and RAM seemed to be inconsequential)... Well one of us got to go swimming that day, and it wasn't me! Even if he had been correct in his view of the rules (he wasn't) he still was gonna lose. Even in the open sea, were I in a stand-on situation with a closing CPA and on a small boat, I would still give way to a ship; to do otherwise is arrogant and foolhardy.