I would argue that when Morse skills were necessary to get on the HF bands, operators would come across the abbreviations in the course of learning Morse. Now it is not a requirement, ergo they won't come across them and may very well not even know that the abbreviations are used when operating Morse code. Reading an operating manual maybe useful, although even then, the application of the abbreviations in other areas such as QSL cards is not necessarily obvious.
Well, to be fair, Morse skills WERE required to get on HF when this thread was started, just saying. But I agree with the general sentiment that it was a fair question and a good place to ask it.
Also, I wanted to participate in a 13 year old thread, woot!
(let it die)