I labelled this "BS", but I suppose it could also be folklore.

Many, many years ago I was watching an episode of a TV Western (very generic - I don't remember the title.) In a scene, a man came into the office of a former employer and said, with cold anger in his voice, "You wrote me a broken crane letter!" A third man was present who said "what's that?", which gave the first man an opportunity to provide exposition for the TV audience. He said that the former employer had written a letter of recommendation that included, somewhere in the margin (or perhaps it was a watermark), a drawing of a broken crane (I don't know if it was a construction crane [how common were they in the days of the old west?] or a bird.) Any prospective employer, seeing this broken crane symbol, would know that it meant "pay no attention to anything I have written in this letter - you don't want to hire this person."

Has anybody ever heard of this? I tried a GOOGLE search on "broken crane letter" and got nothing. Is this a reference to something real, and the scriptwriter changed the name of the symbol? Or did the scriptwriter make the concept up out of whole cloth?

This sort of thing may still go on today. My wife informs me that if a letter of recommendation describes a person as "a hard worker", employers know not to hire the person.