They did remove abused delegations a [couple months ago]( https://steemit.com/spam/@remlaps/re-personz-re-remlaps-re-personz-i-run-sadkitten-so-you-don-t-have-to-dealing-with-massive-amounts-of-spam-20170812t004209670z).

@transisto and @personz reported abusive accounts somehow and @transisto said they got timely results.  I don't know how the accounts were reported, though.

There really should be a published process for reporting  suspected steemit delegation abuses.  That's a slightly different case from someone voting their own steem power from multiple accounts.