If I was boat 3 and only made a small course change, I would not protest boat 1 because they tacked back to starboard, fulfilling their obligation as a give way boat. The way you describe the incident it sounds like boat 2 might be most at fault for not either passing along the hail, or providing room for boat 1 to duck. I honestly don't think boat 3 was pushing the rules. They were a starboard tack boat and received no hail for room to tack.
In the situation you are describing, the pin end boat is taking a calculated risk with their starting position. If you get a good start, and the pin is slightly favored, you are first to the beach/pier and that can be a race winning move. If you don't get a good start, however, you need to be prepared to make a lot of painful ducks on port because you know there is going to be a line of boats that started further up the line and are all trying to hold all the way to the obstruction. This situation is very common when there is current relief against a shoreline.
Somebody has to start at the pin.
Again this is my question: If there is room to tack but not clear at what distance point etc is the requirement enforce to pass along or follow the hail? 1 might be able to pull off a full 180 tack to enact a duck or if 3 pushes its starboard rights 1 feels it cannot safely pull off a duck and has to immediately tack back into a no water situation.
My point above about people playing clean is if this went to a committee, it is likely to become pure speculation on the outcome at most events. This whole room to safely manouver really depends on the skill of the sailors in question. Who is pushing it, who is calling this issue and how do you judge being fair.
