I agree that is a potential problem, which is why I don't endorse tying these rankings to automatic rewards. The intent is to draw human attention to potentially undervalued posts, which I think decreases the incentive for that kind of fraudulent voting. Drawing attention to low quality posts may be more likely to result in downvoting than upvoting.
We also filter our voters with low reputation so it wouldn't necessarily be a trivial undertaking to not only register many accounts but also increase their reputation. At that point, you'd probably be better off consolidating all of the reputation and goodwill, not to mention steem power, in one account.
Finally, aawwww, bunny gifs!
I think that you do an excellent job at exposing people to potentially undervalued posts, and I like your angle on things!
Glad you liked the furry little ones!
Keep it up!