you would be much safer with an edged weapon, kinves are VERY difficult to disarm without getting hurt, howeverm your average person can disarm a gun, before they get shot...
essentially, you can be attacked from 46,656,000 degrees (360 degrees x 3 dimentions) a gun can attack in exactly 1 degree, all a person needs to do is make sure that 1 degree is not where they are...
a human's visual analasys time is approx 190 miliseconds, which means that if you are holding a gun to someone's head, it will take 190 miliseconds after you actually see them move, for your brain to realize that they are moving, there is another period of time for your brain to make the decision to pull the trigger, and then another period of time for your brain to tell your finger to do it, then 1 more period of time while you actually are pulling the trigger...
i don't know the actual number, but this, best case scenario, if you KNEW the guy was going to try to snatch the gun from you, is somewhere around .3 seconds, then there's the time for the bullet to leave the barrel, any movement of the gun, while the bullet is in the barrel, will cause the bullet to go somewhere else... yes this is a VERY short period of time, but we are talking total, less than half a second...
additionally, if you were holding a gun to someone, you're going to be pumped with adrenalin, yes this gives you a better physical advantage, but it puts you into the fight or flight mode, which hinders your thinking and control, so your reaction time is going to suffer...
all a person, who is trying to disarm you, has to do, is knock the gun out of aim, within that .3-.4 second window, then proceed to wrestle it away from you... go get a friend and a water pistol, try it outside, tell them when they see you moving, trying to take the gun, to shoot, but don't shoot before that, stand facing them, and when you are ready "snap" and twist, all you have to do is slap the barrel away from your body, and you've won for now... the actual disarm from that point on is a little more tricky, but they are only going to be holding the gun with 1 hand, and you will probably have both on there before he consciously knows what's going on... and most people who have no training in this manner, when they get startled (which they will) open their hands and put their hands up, as a reaction to not get their fingers caught in machinery or under a vehicle that's falling, or something like that...
knives on the other hand, they attack in roughly 23,000,000 degrees... and there is a lot less real-estate to grab, most of which you are already holding on to... the chances of them disarming you without getting cut (unless they are spesifically trained in disarming edged weapons) is like 1:10 if that... and even if they are trained, they still won't do any better than probably 50/50...
in canada also, it's MUCH easier to justify carrying a knife than a gun, a knife is a tool, a gun is a weapon, that's law... any tool that is used to injure or hurt a person is classified (if articulated properly) as a "weapon of opportunity" it would be like you found it on the ground while fighting the person... you didn't have it spesifically to harm someone...
same kinda deal with pepper spray, in canada pepper spray is illegal, HOWEVER, dog spray (pepper spray with "dog repellent" on the can) is legal, because it's designed for a dog, not a person... it's not a weapon, it's a tool... if you happen to have it because you are scared of stray dogs, and use it on a person, you can articulate it, and will most likely be found justified... (pepper spray is classifed as a restricted weapon, and carrying it can land you in jail, regardless of if you use it or not, butterfly knifes, switch blades, collapsible batons and brass knuckles are also in this category)