Re: Real attackers attacking again
I used aikido after training for 1 year, in a self-defence situation, and it was effective. I think it really depends on the situation - you could train for 50 years and still be taken by suprise. The things aikido teaches you that are useful is body movement and a positive response - aikido in reality is rarely like that in the dojo. Training is there to condition our reactions.
People let go if you tug them or force them. Good aikido blends with the opponent so there is no 'letting go' because you follow their movment. i.e. if they withdraw you move in. A long time from now you may realise that there are not different techniques - your movement follows the attacker's and the technique should naturally drop out of blending with them. Thus you don't have to 'swap' techniques.
One common response is raising and dropping the arms. This is usually the initial response no matter what the 'attack'. After contact blending is necessary.
The point about being a pacifist only if you have trained in self-defence I think was making a point about having a choice. e.g. you can choose not to hurt somene only if you are capable of hurting someone (otherwise it isn't really a choice). However I don't know anyone who would not be capable of killing someone else (physically), excluding perhaps those in a coma. The weakest person can stab someone in their sleep, shoot someone or poison someone. Therefore pacifism can be a choice for almost everyone.
Personally I think ethics need to be flexible, though derived through compassion.
I know a policeman who did shiho-nage, and the attacker just stood up again and hit him. You need to use the correct tool for the job. If your life is being threatened, esp. in multiple attack, I would suggest incapacitating people (which is possible with aikido) or a quick get away. If your kid sister is slapping you, I suggest less aggressive action.
It is a big error to over-generalise about real self-defence situations. My policy is train not to harm people but be aware how to. Your brain can work very fast in real self-defence situations, and hopefully with training your body can as well.