When I was a child in the 1950s I remember a comic book story of visitors from outer space. The aliens were hovering above Washington, sending strange signals to our government and military.
The code was finally translated and the officer typing it was being pressured and rushed. He handed the translation to the commander and said, "Wait, I may have made a mistake, let me read that again."
The General ignored the typist, read the message and ordered our aircraft to strike the space ship. The aliens retaliated and our planet was disintegrated.
The text on the page read, "Deceive us and we will descend upon you." The pressured code breaker hit the letter D when he meant to type the letter R.
The message was friendly, "Receive us and we will descend upon you."
In this case, one error was earth shattering :^).