The database could be designed to record that you voted for a particular node without recording what your vote was

Yes it could. But then we wouldn't be able to detect people misusing the voting system. We keep this data to prevent others from abusing, not to abuse it ourselves. Also I think its kind nice you can tell how you voted on a node from the RAT. Of course, I would say this, as it was my idea anyway, but you know what I mean. :-)