The public perception of computer systems is that they are mindless robots who interpret commands from operators literally and then follow through with them relentlessly, even when the operator realizes he made a mistake. There is actually a lot of truth to that perception.
This goes back to what I was saying earlier about this being a very old problem indeed--there's a famous quote from Charles Babbage that describes this exact issue:
"On two occasions I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question."