[saltcured]

Not without some kind of delay function and probably filtering/evaluation of which new accounts get this capability...

Everyone here should be familiar with exponential growth of n-ary trees. If you can get one of these accounts and each new invitee gets to invite 2 more, you can already have accounts gone wild.

[sowbug]

If it's a tree, it's easier to prune an entire branch that's gone bad.

[hedora]

So, the scammer should send an invite to a real person from one percent of the accounts in the tree, wait a few months, then flip the evil bit on 90-95% of the accounts they registered. If the whole tree is cut off the reputational damage is really high (10,000 valid users nuked because of actions other accounts took...)

[sowbug]

Yep, it's a never-ending escalation.