In the "real" world we keep our relationship bubbles to a small number for just this reason - we have our close relationships, the people we trust, and then we have gradually less and less close relationships - people we know to greet, or know have done x or y or z

We know that people who are on our outer orbits should not be shared with in certain ways.

Our communities are in fact lots of overlapping bubbles, x knows y, and y knows z, but x sees them as a stranger.

The internet changes that dynamic, and we don't yet know how to manage it - we cannot all live in the town square, and we know to be very careful there, pickpockets, thieves, and robbers abound - and we have no idea who is who

Again our historical approach has been places like universities, where we have "trusted" advisors (teachers) who guide us on subjects being discussed openly - but who also ensure that we avoid pitfalls, like heated debates where people abandon logic and instead use rhetoric or violence, and who ensure that commercial interests are managed - that is, some advertisements are allowed, but unauthorised advertising is forbidden

That approach (moderation) has its own set of problems

Apply whatever rules, caveats, and process you want. I never said an invite tree was an automated one stop shop solution. Just that it’s useful for identifying spammers and how they’re connected. Stop trying to design a single one size fits all solution for every problem angle and you will see rules and systems working together.