I have a couple thoughts on the subject. Let's start with why you might want to do such a thing. I've been reading "Deep Survival - Who Lives, Who Dies, and Why" by Laurence Gonzales, and I thought there were some excellent points in the book. For the purposes of structuring a coherent argument, let me quote a section of this book:
"When you learn something complex, such as flying, snowboarding, or playing tennis or golf, at first you must think through each move. That is called explicit learning, and it's stored in explicit memory, the kind you can talk about, the kind that allows you to remember a recipe for lasagna. But as you gain more experience, you begin to do the task less consciously. You develop flow, touch, timing--a feel [emphasis added] for it. It becomes second nature, a thing of beauty. That's known as implicit learning. The two neurological systems of explicit and implicit learning are quite seperate. Implicit memories are unconscious. Implicit learning is like a natural smile; It comes by way of a differnt neural pathway from the one that carries explicit memory."
He goes on to say that:
"Implicit memories are not stored in or necessarily even available to the analytical, reasoning part of the brain."
He also states that you teach the implicit memory differently than the explicit memory. To teach the explicit memory you speak and make arguments and use logic. But to speak to the implicit memory you have to change how the information is delivered.
So what does all this psycho-babble mean? When we train, we can not neglect the non-logical part of the brain. We can explain techniques logically all we want, but your logical (or explicit) mind does not have the processing horsepower to step through a logical argument and look up facts and apply them fast enough to stop an oncoming attack. Only your implicit memory can work that fast. This is why we do training drills. We do them until we stop analyzing every movement, and then just start to "feel" when the movements are right.
We are used to the time tested method of reaching the implicit memory--time consuming repetition. But we can make a training shortcut right to this part of the brain. Just as we can simulate firearms (Simmunition, MILES, Airsoft, etc.) we can also simulate edged weapons. As instructors, we want direct access to the implicit mind and we want to teach it quickly, yet we do not want to cause any serious and long lasting injuries. So why not include practicing with a stun gun? You will get a very immediate reaction of fear (followed by pain if a mistake is made), but you will not get a serious and long lasting injury. Once shocked, people will instinctively move out of the path of the "blade". This shows that learning by the implicit part of the brain is in progress. If you get zapped just once you will NOT want to get zapped again. After being shocked a person will go to great lengths to stay out of the way of the electricity. Will they use proper technique every time to keep from getting shocked? No! And I don't care! I simply want them to learn to keep the weapon stabilized and the "point" (in this case electrical probes) away from their body. I'm less concerned with how they do this than I am the fact that they can manage to do it at all.
All of the blocks and responses we have for edged weapons work against broken bottles, sticks, knives, even empty hands. So why not against stun guns? I have a novelty shocking pen that I have handed to people. They try to write with it and get shocked. I pick it up and thrust it at their chest, which in reality would not even cause them to be shocked, yet they jump out of the way like they expect to be electrocuted. They only need to be shocked once to get the benefit of the learned behavior.
The point is not to shock someone over and over. The point is to speak directly to the implicit mind and say "Stop this attack or you are going to get hurt!" Once is enough. All you need to do is cause pain one time, and from then on people will get out of the way of danger without even thinking about it.
I realize this is a bit of a radical view, and that it is difficult to fully explain to a class why it is that you want to do something crazy like train against a stun gun. But I think the method has some merit.
The same goes for firearms training. I do firearm disarms against live, high power Airsoft guns. If I make a mistake I get hit and it hurts like hell (always have everyone wear a face mask). It is as real a simulation as we can ever get. The Airsoft BB goes in the same trajectory as a real bullet. It's easy enough to determine what would have happened with a real firearm.
Frankly, I would like to see the development of a stun gun shaped like a knife where the "edge" was electified. I think this would make an excellent training tool.
I've used the stun gun method on some willing students and have gotten excellent results. You can't just throw them into the deep end. You start with all the same basic blocks you always teach. Then you say "OK, I think you have it, let's test you and make sure." They may get shocked once if they make a mistake, but I do not set out to harm them. I give them a fighting chance, and if a probe hits them, whether or not it is electrified, they will act as if it is and get out of the way. If you can keep from getting shocked then you can certainly keep from getting stabbed. It is simply amazing how immediate the response to this training is.
This is still a rather new area for me, and so far it seems to work quite well. I'd like to hear from anyone else who tries it.
Good luck.