Trained Versus Untrained?

I have heard it explained, by many people, that Karate is designed as a method of Civil Defense against untrained assailants.
It is meant to be quick, effective, and straightforward in its' application to ensure the safety of the victim in question so that they could go on farming, fishing, or whatever it was they did to earn a living.

I have also heard it explained the other way, using battlefield references to explain things in Karate and other empty-handed arts (Which I do not buy even for a minute). The fact remains that there are flaws in both, for one, the second explanation is obvious since the primary focus of development for Military Organizations has been weaponry, with empty-handed techniques being secondary or very nearly excluded.

The first tends to have flaws in the fact that we assume certain things on the part of Criminal Activity.
For one, no Violent situation is exactly the same as another and there are too many variables for which to account, second, we cannot assume that Criminals are not trained, at least by experience in their particular modus operendi.
Even this was a particularly individual sort of thing, and one could not assume there was no other training on top of that.
A person who deals in violence on a regular basis knows violence really well, they know what works for them and what does not, they are also not rocket scientists and are often looking for an easy kill.

Would we run into a drunk Martial Artist looking for a brawl? Sure, we may, there are Martial Artists in prison who train and teach others.
I once watched a program about a Gang that trained specifically to kill with one or two hits, there is also the problem (whether it is true or not) of the Prison Fighting Method called 52 hands boxing.
These are methods, granted, and we will not see adherence to methods in emotionally heated situations, but in one-sided situations we might, there are definitely possibilities.
Even in the old days it is a bit much to assume that an assailant attacking a Karateka was not trained or had no experience; experience is a given, and one can learn loads with experience as their Teacher - couple this with the notion that some of these Criminal types may have this all down to a science, or perhaps even had Formal Training on top of that, the can of worms is open.

I cannot let things rest on assumptions, there are too many variables to consider and I have met my share of questionable characters that were more than capable AND had training (often years of training, even a few decades, WITH formal teachers) on top of that.
Getting down to it, they know exactly how to exploit, on top of what they already knew by experience, they exploit what they have learned via training.

So Karate, nor any form of Budo, MUST address the problem. It cannot assume untrained assailants, just as it cannot assume trained and competent assailants in any situation.