Re: What is "combat"?
Not sure about cops...but soldiers don't have "scenes that go bad". They have battles and fights, in which they fight, die, win, and survive (hopefully). Might be semantics, but I think it is important to look at it in the proper light. It's not like we are trying to avoid the situations.
I don't think aikidoka are unique at all, or have a corner on the market of choice concerning how hard they get to do a technique. I think the way we train lends us to think that way, which I think is dangerous thought. Certainly training and skill can expand they choices you "might" have, but aikidoka don't own it by any stretch of the imagination.
Ethics are on the person, not in the techniques...techniques are not ethical, only the choices we make to take action. Again, aikidoka study to be ethical I think, but that does not mean we have more or less skill in what we do when acting in a martial capacity. Ethics I think are a mental thing or a state of mind.
Maybe Shihans can or can't do this. Certainly in a dojo in a controlled environment they can demonstrate the range and skill that is possible...I don't think though it directly transmit to reality. They may or may not be able to demonstrate the same level of skill or proficiency in a combat environment over anyone else....too many variables!