"Until recently I was very anti-knife carry, as all of my preconceptions were negative towards all those that do, now it's just against the majority that do."
An extremely bigoted and uninformed view. A knife is a common tool and most people carry knives as tools. Very few carry, use, or know how to use knives as weapons. According to an article I read in a knife magazine a few years ago on the criminal use of knives, even most criminals who use knives use them as tools, such as for cutting things when breaking and entering.
Hollywood does not equal reality. The average knife user is not Norman Bates.
"However, even though I would prefer to have an 'equaliser', or, more directly a 'frightener' when a situation may become dire"
If you want a "frightener" carry one of those personal alarms. It probably won't do much good, but it is better than brandishing a gun or knife with the intent to scare and no intent to use. Doing that would be a good way to get killed.
"I'm really not sure how a knife can really be a weapon of self-defence?"
Buy some DVDs and manuals, such as TM 1-3.
"It is made for killing,"
No it is not, it was designed as a tool that people later used for killing. Most knives are made for other purposes such as cutting things. There are a few knives made for fighting such as daggers, dueling Bowies, actual Japanese tanto (well, that is actually a sword) and a few exotic knives, but for the most part a knife is made as a tool. Specialized fighting knives are only a very small minority of the knives carried, and although I prefer single-edged knives as tools, there are people who like double-edged knives so they can take twice as long before sharpening or so they can have a rough edge on one side and a very fine edge on the other. Some people also mainly cut cardboard, packages, and rope and almost any knife will do.
Do you really think most people who carry knives do so for killing? When was the last Boy Scout Camp massacre?
"and most of the knife attack training I've seen and experienced is geared towards a kill!"
Most modern training I've seen is geared towards stopping the attack. Traditional martial arts do tend towards killing, even finishing off an attacker, but just be aware of that and don't include finishing in your personal practice.
"I fully understand those in the military, law enforcment or on the hard line of security carrying any type of blade, but what about Joe civillian?"
So you are an elitist who thinks "civilians" should be unarmed pesants? Why should they be treated differently from police and military? It can't be a training issue, since most private citizens who happen to be practitioners of blade arts have many times more training in blades than either police or military who do not train in blade arts. Those police and military who do train in blade arts would be more like private citizens who train in blade arts in terms of blade training. The skill issue is whether someone trained or not.
"If a knife is carried for self-defence then shouldn't it be as big and scary as is practical to carry, as opposed to a small concealed hideaway knife?"
For a fighting knife, a Bowie, Smatchet, or kukri might be a good choice. Most don't carry knives for fighting, however. There could also be state and local laws against carrying large blades.
A full-sized Bowie can be easily concealed, even when wearing knee-length shorts and a t-shirt, assmuming you have the proper rig. If you are carrying a knife primarily for defense and really do want a big knife then you might want to go this route with a Cold Steel Laredo Bowie, Cold Steel Trailmaster Bowie, or one of the Ontario Bagwell Bowies, assuming it is legal in your area.
Another factor is not what is legal but what the proscution will do. People have acted entirely within the law and have been unjustly, but "legally," imprisoned, and others have committed murder and got away with it. In a way "what is legal" depends on how good your lawyer is compared to the prosecution, which pretty much means that "justice" depends on how much money you have. Considering this, carrying a smaller knife without a politically incorrect name is a better choice. While many people are patriotic, even the word "military" is un-PC and more Leftist prosecutors have used the name of a Spyderco Military against the defendent. Names like "Endura" and "Delica" are neutral and better choices. Avoid knives with words like "combat," "fighter," "warrior," etc. in the name.
"Scary" is a personal opinion and not really a logical criteria for choosing a knife. A fantasy knife might be "scary" but it would probably also be a piece of junk meant only for display, even if it costs over $100.00.
As the vast majority of people who carry knives carry them as tools, they usually carry something as small as possible that would still be useful for what they intend to use it for. Some jobs require big knives, but most people who use machetes would keep them in their vehicle or wherever they will use them rather than carry them around town.
As for me, I've carried a knife of one type or another since I was a Cub Scout and never really trained in bladework to any large extent until I was in my mid-20s. I figured that since I always had a knife it would be a good idea to learn to use one in defense.
"Surely, as soon as you have to use a knife to defend yourself, it immediately becomes a killing intent mentality?"
That all depends on the situation.
You are also missing a few steps in a self-defense scenario. One is situational awareness to know when a problem is likely to occur, and another is avoiding the problem, and another is evaluating the situation and responding in the proper manner.
"As an aside. How many people who 'play' at knife training have ever used a blade for real, even on a dead carcass?"
I use my survival, fighting, and utility knives in the kitchen and for yardwork such as clearing trees and other vegitation and cut various targets. I sometimes use big survival knives in the kitchen to prepare food and pocketknives as machetes to clear vegetation for practice in using them in non-optimal settings.
"I've slaughtered, skinned and gutted a few animals, so I'm not squeamish about cutting something up."
Now this is confusing. You admit to using a knife as a tool, yet you condemn most other people who carry knives? Isn't it possible that most other knife users use knives as you just admitted to doing?
"but to knife someone for real, even when up against the wall? That would really have to be a life or death situation.."
Again, you are missing the whole point in using weapons in self-defense. When using a weapon that could be lethal force, you only do so when the attacker has the ability, intent, and means to kill or seriously injure you or another person.
Take a combat handgun or CCW class to learn the laws in regards to the justified use of deadly force in your state.
