Yes that's the idea. Moderators would downvote content that's overpaid. It doesn't really matter if it was upvoted by many sockpuppets, if the content is shitty payout will go down.
foundation
Another incentive for whales to not split their account is that by letting other users vote they will increase the demand for steem and so the value of their account.
This has not been enough of an incentive for many of them to curate responsibly in the past, and there is no reason to believe it will in the future.