Re: To help or not to help
I have worked the past ten years on a prison yard. My partner and I supervise about 200 of California's finest citizens. The answer to whether or not you intercede in an altercation is entirely scenario specific. A proper threat assessment, is paramount. What is a proper threat assessment? Maybe we should consult Sun Tzu. Know your enemy, know yourself, know your environment.
In first aid you are taught that your safety is paramount in attempting to render any kind of aid. I think, in this subject, the tenants of first aid hold up. First you call, to summons help; then you take whatever action you can safely take, within your scope of knowledge or ability, as long as the scene is safe to do so.
Now you have already called for help, or had someone call for you. Next, identify the players involved. This may prove difficult. How do you tell if a particular onlooker or group of onlookers is associated with one of the combatants? The easiest solution is to assume all of the onlookers may be associates of one of the combatants, or at the very least hostile toward you for trying to interfere with the fight. If there are onlookers not trying to break it up, assume they are hostile. Try to get some of them together to assist you in ending the fight. Who knows, maybe both combatants are equally represented and either side can successfully pull their guy from the fray. You have to know your abilities and whether you can successfully convince a good number of them to help.
Knowing yourself and your abilities is important, because you don't enter a fight unless you know you can win. You can't know this unless you have seen your adversary in action and are honest with yourself and what you can accomplish. If there are no onlookers, you had better be sure of your skills before you attempt to break up the tussle.
It is much easier to apply Aikido techniques as a third party for sure. The two are focused on each other and the window of opportunity to slap on a sankyo or nikyo is wider, than if one was focused solely on harming you. If two are actively fighting and able to defend themselves, I wouldn't intercede till one was unable to put up a successful defense anymore. A this point, you aren't likely to face two who turn on you, and/or the dominating one is more likely to listen to a third party saying he won, or the other has had enough.
Obviously if there are weapons involved, unless you have some sort of force multiplier to answer whatever force is present, the scene is unsafe for you to intercede. About all you can do, after calling for help is be a good witness. Even if you spent three classes a week on tanto-dori, you most likely won't want to intercede in a scenario where someone has already shown the willingness and ability to use the knife on another human being. The threat of death or great bodily injury is present, and the gun carriers on here would be justified in the use of deadly force in many places.(check your local laws)
As a parent, or someone with anyone else in my care, interceding while with the kids or maybe a girlfriend, or wife, is never wise. For one, you don't know what you may be called to do or what they may see. If you go down, they have no advocate. You commit those with you to something they may not be prepared for. Still, take what action you can safely take. If this means simply calling for help, then that's all you can do.
As an average citizen, are you legally obligated to help someone? That depends on where you are, and what the law says. I believe most places, today calling the authorities is enough to satisfy any obligation. If you feel you have a moral obligation, because you train in Budo or whatever gives you the feeling of obligation, weigh your obligation to the stranger to the obligation to your family, friends and employer. I still hold that you are not obligated to render aid if the circumstances of the scenario are beyond your abilities.