Haven't tought much about the removal (or checked POB) but worth 10 or 100x less than the upvote power also comes to mind. So that there is a "warning" before any post is removed of rewards or like ura was saying an area for the most downvoted posts, i'm thinking with hive getting more expensive it would be hard for regular accounts to counter this without further action.
Thanks for bringing up for digestion ;)