BlackBoxVoting.org reports that the Diebold electronic voting machines can be made to change the vote totals by entering a simple 2-digit code:
By entering a 2-digit code in a hidden location, a second set of votes is created in the Diebold central tabulator, a program installed in 1,000 locations, which controls both paper ballots and touch-screens, each system handling up to a million votes at a time.Our worst fears: [BlackBoxVoting.org]
After invoking the 2-digit trigger, this second set of votes can be changed so that it no longer matches the correct set of votes. The voting system will then read the totals from the bogus vote set.
It takes only seconds to change the votes, and to date not a single location in the U.S. has implemented security measures to fully mitigate the risks. It is not too late to do so, and the corrective measures are relatively simple.
This program is not "stupidity" or sloppiness. It was designed and tested over a series of a dozen version adjustments, and has been in place for four years.