[wongarsu]

There is the simpler version that is approximately "you can only get in if someone vouches for you. If a person you vouch for misbehaves you get punished as well". That's effectively a "tree of trust" with skin in the game. And it's incredibly successful, used in lots of communities, crime rings, job recommendations, etc.

Any attempt to generalize this by allowing multiple weak vouches instead of a single strong one, or allowing people to join before getting vouched for, or removing the stakes in vouching for someone, etc. always end up failing for fairly predictable reasons. No matter how much cool cryptography you add

[berenddeperend]

Wouldn't that be easy to bypass by just adding one or two proxy accounts? Say person A invites me (a bad actor). I could invite a second throwaway account, with which I invite a third throwaway account. I do bad things on my third account. Could you reasonably punish person A for this? You'd first have to prove that the throwaway accounts all belong to me.

[lukan]

No one has to proof anything. If A invites B and B invites C who acts openly bad, you can remove all parties at once and maybe revoke on appeal. All up to the community. Otherwise it would be indeed simple to defeat. But before banning A, one can also just give a Warning. No restrictions here in principle, but I am also open for concrete implementations that work well.

[account42]

The point is that either there has to be a limit for how much you get punished for the acts of your grandchildren, which leaves room for motivated abusers to work around your system, or people can expect to be banned for basically no fault of their own if they ever invite anyone, in which case your system is DOA.

[lukan]

The point is, it is a balance each community has to find on their own. In reality this means adjusting depending on incidents. But if A invites B who openly does bad things, it very much is the fault of A to drag this person into the community.

[Miraltar]

Create some sort of score that goes up when a "child" misbehaves. The further the child the lower the increase but at some point you get banned anyway