I think you're emphasizing the value of pre-decision making required to evaluate why to use a signal. I agree with that, but part ways when -basing this on the original post I'd replied to -your perception (notoriously not 100% robust BTW, but I haven't got time nor the patience to go through human psychology 101) says there isn't another road user around that will benefit from it.
Again, I'm open to persuasion, but I haven't seen in your response (and I do understand your adherence to a decision making process such as Roadcraft, and it is very admirable as it's a great system) any substantive reasoning to deliberately not signal when it's safe to do so, even if there is a perception no road user is there to benefit from doing so, versus signalling under similar conditions based on the reasons I'd outlined (again, open on this one as you never stop learning). In fact, aside from safety reasons, when would you deliberately choose not to signal after going through the decision making process?
Maybe I'm just a rebel livin' on the edge of the Roadcraft system..... anyway, let's hope for safe cycling and road use for us all -bet that's one thing we agree on!
I have also completed the IAM advanced Motorcycling test using the Roadcraft system but I'm in agreement with your points. I make the decision to signal even though at first looks there may be nobody around that can see it. If one day that nobody I didn't see beeps me then I will have been justified and proud to have been a rebel.
I find it ironic that these same car drivers who bully cyclists haven't got the balls to do the same to motorcyclists when in the exact same position on the road. Why do they really think that cyclists or motorcyclists can't actually see them gradually move right or left to prevent them filtering?