[wittystick]

The only thing that isn't potentially misinformation is that which you witness with your own eyes. Since everyone has their own eyes, calling what they witness misinformation is known as gaslighting.

The only way to prevent people sharing their experiences is called censorship.

What you're really asking is "can we stop people from lying?"

The answer is no.

[muzani]

I think you found the root, but let's go a step up - can we prevent lies from spreading?

It would seem like similar to stopping cancer or other bad things from spreading.

Fun story: I was involved in starting a fake newspaper just as a bit of hacker mischief. It spread fast on Facebook. FB eventually found a way to clamp down on fake news without needing downvotes, and later Google did. The only traces left of it are Snopes articles today.

[wittystick]

It's just a terrible idea to even contemplate trying this. The solution to misinformation is an informed public, which doesn't come about by censoring information, but allowing unfettered access to it so that people can make an informed judgement.

Who even decides what is misinformation, and how do you prevent them from lying and spreading those lies themselves (or lying by omission)?

In 1615, authorities labeled Heliocentrism as misinformation.

The Chinese authorities label the Tiananmen sq. massacre as misinformation and "prevent lies from spreading."

Even many of today's "scientists" are dogmatic in what they consider misinformation because they have an all-knowing god called "peer review," and some of them promote censorship.

This is the kind of thing where the censors think they're doing the world good by "stopping the spread of misinformation," but they will be the historical villains in future because all they're doing is giving an authority the powers to misinform the public, because any information these authorities don't want spread can be labeled misinformation.