On the new review tab and while reviewing 'First Posts', there's a line inviting to vote up or down.
I did vote down a bad answer, and left a comment. I was surprised to see my rep go down one point. Not that I care too much about rep, but for doing my civic duty as reviewer, I expected a free ride.
I propose to eliminate the reputation fee when downvoting on the review tab.
Edit - Addressing criticism:
A downvote = a downvote = a downvote
No it's not. To be able to do a review, you need at least 2K.
Also, for reviewing, you receive a 'Custodian' badge. It's like a peer reviewer on a scientific magazine. You'd expect, at least, a free copy of the magazine you helped to peer review (not sure if that happens).
You can trick the system
What? How? The revisable items are picked by the system, so you cannot target one specific person.
I don't expect 2K users to do that, but it would be a good idea to have a filter or a threshold in place in the review tab. So, if somebody hands out 10 or 20 downvotes in quick succession, in review, these get flagged or something.
Why bother for only one point?
For >2k users, one point shouldn't be a deterrent, so it may not be worth the hassle to program the exception into the system. That's a good point, IMO. I'm not saying this should be high on the priority list. But I don't think we should think for others (the stackoverflow team) when making proposals. If the proposal is worth it, it'll be done, in due time.