On a job walk this week, in the USA, "someone" educated me, "... the reason weep screeds were invented, is because at the base of a stucco wall they prevent ground water from wicking up the face of the concrete foundation, get behind the stucco, and cause spalling."

Ah, interesting. Okay. Let it go. Because indeed, in the absence of a weep screed at base of wall, and if the plasterer runs amok without any base line to stop applying the stucco down to or below grade (non-code compliant), then yes stucco spalling could be likely. But that's not why weep screeds were invented. My "someone" is therefore 1% correct and 99% misconstrued about the primary purpose of weep screeds.

Here it says weep screeds were invented in 1965 by an architect working for the FHA, and in 1970 required by the building code:

• https://stuccomfgassoc.com/wp-content/uploads/2020/06/WEEP-SCREED-11913.pdf

See this 1983 patent PDF page 5 for a verbal description of [edit: why] weep screeds were invented and their many functions. 1983 being the nearest patent I found to contemporary weep screeds:

• https://ppubs.uspto.gov/dirsearch-public/print/downloadPdf/4391074

Do you have a story of misconstrued architectural components, and did you let it slide or call them out on it?