> You don't have full control over the knife. In fact it's not about your use of the knife.

There are many knives in your relative proximity all the time. Some of them are used for your benefit, other are used for other's benefit, every one have potential to be abused against you by evil actor.

> The people in control of the knife have a poor track record at caring about you, and belong to a category that history has proven we should not trust.

Scrutiny should be proportional severity of harm times the frequency of harm.

> Every time you use the knife, you sign a blank contract giving full authorization to future non-specified knife usage to people you don't know nor do you know their motive. And you trust none of those people, for an indefinite length of time, will abuse it.

Everytime you enter restaurant or even leave your house you are giving full authorization to people around you who posses knives to use those knives for non-specified purposes. You can only hope they are reasonable and won't cause you harm.

> Cumulative use of the knife can accumulate stabs that may be delt to you and all your love ones one day all at once

Knives don't need to accumulate anything. One misapplication can end your life literally

> Use of knife can be automated and scale at the level of all countries.

There are many machines that are basically bunch of fast moving knives. It's on you to not be where they are. Their operators are bound to take precautions proportional to harm times the frequency of harm.

> Most people are not knowledgeable about the knife, don't know much about it, and it's invisible to them

You usually can't really tell how many knives are around you and most are hidden at most times.

Some places don't. Some do. In Poland news about ban on knife carrying was April fool's joke. In UK it's a serious law with serious punishments. In UK people who'd carry a knife with malicious intent just moved to carrying caustic chemicals. It's often not specific tech that's a problem, but the culture and incentives for its misuse.

Although reasonable restrictions on all technologies aren't inherently bad.

Restrictions imposed pre-emptively just because nightmare scenarios are easy to imagine and captivating are not great.

People say "monopoly on violence" as if it's a bad thing. As if the opposite of that is no violence at all. But the opposite is commonality of violence which was the case before government became strong enough to enforce monopoly on violence and still is the case in places where the government is weak enough to lose the monopoly.

Monopoly on violence is the most significant cultural development that allowed incredible wealth and societal development.

Currently we are in the age of commonality of surveillance. If this turns out to be harmful enough we might as well move towards monopoly on surveillance and it might be an improvement.

Personally I think it won't be necessary.

I'm sure of one thing. Surveillance won't go away because it's a useful technological tool.