Looking into this after a good night's rest.
I see some have joined flagging, good!, and this scheme seems to have halted operations.
It brings up a few more accounts that were obviously created to do the same. User @yarmolnik has set up a chain of numbered comments 2 days ago. If the culprit follows the same pattern, these will start being upvoted shortly before rewards get paid out. See their [recent comment].
This needs to be monitored, I'll keep it under check, but my VP will not suffice to kill the payouts!
edit: self-upvoting my previous comment for visibility... meh