This is of great importance and i would also suggest the psychology of an armed person. For a breaif explanation of what i mean lets take the guy who brandishes a knife as a threatening tool. Although he may use it he is less likely too and by understanding the postion the opponent is in, often wanting to get away as cleanly as possible. This situation is esque of many muggings, and your own psychology comes into play when you weigh up what is in your wallet etc. vs. the value of your life. I generally advise keeping distance and cooperating in this situation. Another similar situation i have seen has been in security work, a very desperate guy armed with used heroin needles (possibility of HIV) really wanted to get out and his temper was very volitile. Generally we give him a free path to the door so he feels less trapped and has an escape from his situation. Don't worry he was apprehended but his state of mind had to be controlled in the dangerous situation. The point is many people treaten with weapons out of fear and this makes them unpredictable, of course you can train for the situation when you have no choice i know i do and training with a couple of rubber knives is actually great fun when you play with a million possibilities.
Of course if someones intent is to stab you then the chances are they won't show you a knife, in fact they may not even show themselves and take you by supprise. There are many ways to brandish a weapon so no one can tell until it is to late, understanding this is also an important aspect of the training as well as how to react if you have been stabbed.
Yeah, the kwoon is a great place to come up with and work as much defence work, remembering defence work doesn't always mean engaging the opponent. Reading the situation is important.
Yeah the idea isn't to give you a million and one answers to the same question that you then have to choose the right one, its about training good complete movements that work quickly and effectively without involving the mind - this leaves the mind free to referee the situation.
Its something i've heard many a time from my sifu and others "don't add more add less". Again you can add and add and add and eventually end up with a different tool for every situation and then you can add tools for every varience and this just takes up a **** load of system resources and gives you a huge system. Wing chun is a small system and a complete one at that, yip man made a lot of refinements in the system but it remained complete. I see this on a personal level now as i will mould wing chun to work as a complete system for me, i may find ihave a tool that covers x and y and a tool that just covers x - do i need the latter tool? Now the thing to remember is that this is a personal thing so when teaching you must give the student the benifit of the entire system not just the system that suits you in order for them to take what works for them and refine it.
nice post by the way.