[vintermann]

Inviting people who invited bots chould also hurt your "social credit" score in various ways.

Your tree could for instance be pruned - you can still invite people, but the people you invited can no longer invite people.

There are not a lot of sites which have tried this and failed. Those which have tried to be even a little bit clever about it, have succeeded pretty well (Advogato was a really early example).

What there have been, are sites which rejected such restrictions after a while, because they would rather have a big number to show to investors than real people. Many have even run the fake accounts themselves (e.g. Reddit).