Again, a classroom exercise, and perhaps a test question, but a prudent operator is not going to proceed into a collision situation blasting his horn because he has the right of way. If we are talking a tug and barges, yes. If we are talking recreational trawlers, it's just not worth it to assert our right of way and risk a collision. Picture this if you will:
You are in this situation heading for a sure collision with another boat, blowing your horn. Your wife, by your side says "Honey, you better slow down or we'll hit that boat." Is your response "F**k him, I have the right of way?
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Now let's look at another set of "rules". On the Atlantic ICW, at least, it is common practice for a faster boat wanting to overtake a slower boat to call the slower boat on the radio and arrange for a "slow pass", that is the slower boat in front will slow or stop and the overtaking boat will then pass at a no-wake speed.
This is, of course, a violation of the rules because the stand on boat is supposed to maintain course and speed while being overtaken. If these two boats followed the "rules", it would either take a couple miles for a 7 knot boat to pass a 6 knot boat, or the overtaking boat would speed past the slower boat, throwing a huge wake.
So - we are breaking the rules, but operating with courtesy and common sense.
One more thing - how many folks here display an anchor ball when anchored during the day? It's in the rulebook.