[acdha]

This is such a key point that people forget: this isn’t some academic game theoretical debate but rather a question of how your actions will be perceived by society. If your IP is used to serve illegal content, saying “well actually, …” isn’t a defense and it most likely means you’re getting charged as an accessory to whatever that stranger did. Even if you can avoid legal penalties after years and significant expense, your reputation will be linked.

[risyachka]

I am not a legal expert but shouldn't the prosecutor prove that you knew about the content? Because if yes, this is basically impossible.

[acdha]

It depends on exactly what you’re talking about and which laws apply, but in general the problem for things like this, running a Tor exit node, etc. is that the content is something which people keep secret and the scenarios you need to worry about are related to serious crimes. If it’s, say, a small amount of copyrighted material your ISP will get an automated cease and desist letter but if your IP serves part of the requests for CSAM or non-consensual pornography, classified material, terrorism-related stuff, etc. that’s a very different situation. You might eventually be able to get off in court but that’s years after you’ve been in the news and quite likely had all of your devices confiscated in an unannounced raid (criminals have set up systems to destroy evidence so this isn’t without some justification), and you’d have incurred significant legal costs even if this didn’t cause you to become unemployed.

The underlying problem here is that it’s basically impossible to distinguish between someone naively allowing strangers to use their property and someone who is trying to cover their tracks by pretending to be unaware, and the internet is full of people who will abuse any free service. If it happens once, maybe you can plead ignorance but that’s not a foundation for a robust file sharing network.

[yaddaor]

You are already deep in a legal process at that point and your life might be ruined.