In the November 2009 election in Kentucky, there was a serious discrepancy between how ES&S's iVotronic voting machines worked and how some voters were instructed. Some voters were apparently falsely told that touching `Vote' completed the voting process. However, that only displayed the review screen, whereas subsequently touching `Cast Ballot' was required. Conspiratorial election judges were then able to modify the ballot and cast it. In addition to the fraud, it is clear that the `vote' screen should have instead been labeled something such as `review'. Five insiders were indicted -- including conspiracy to commit vote fraud, extortion, and tampering with grand jury witnesses in a subsequent attempt at a cover-up.
I was just thinking how lucky it is these people were caught. Then I realized... "will have been caught"? Or are we living in Minority Report now, and are arresting people for precrimes?
More info, including accurate dates, here.