Oh, mostly importantly - their self-upvote will only count towards self-promotion. They will get neither author or curation rewards. Sure, a $0.001 upvote doesn't make that much difference. Because this doesn't affect just dolphins but also guys like haejin, however, this turns steemit into a whole different world.
The reward pool comes from how much steemians have invested in the steem blockchain. If some other person can join, abuse exploits and run away with other people's money without any penalties, you're essentially forced to watch as someone else takes care of a big share of your investment for you regardless of what you think of it.
But as I understand it, a self-upvote will still reward your post in the same manner as an upvote for someone else. And in fact, you will still even get curation rewards for your self-upvote. You just no longer have the advantage of reaping 100% of the curation reward from your own vote when you do it instantly. In other words, only the portion of the curation rewards not awarded to curators because of early voting penalties is affected. I suppose this can be significant it just seems like it would be a relatively small part of the gains one gets from self-upvoting.
I've turned this answer into a new post.