When I arrive at the site I have to log in each time. However, this time I forgot, and I was browsing the Community>Ideas section, and I noticed that a lot of the items were highlighted with blue dots that I knew I had never voted for. I was able to click them and remove the "vote" and the count went down. I'm not sure whose votes I was adding/removing, but they weren't my own since I wasn't logged in at the time. I made sure I left all votes in the state they started in.