I don’t think it’s a policy to always spell out acronyms every single time. I lean towards supporting this one though
In a perfect world all acronyms would have a ho er over feature with the full name. Even commonly known acronyms are obnoxious when you are just getting started.
Yes, however, Anki (and by extension, our deck) is not a teaching tool, it’s a tool for reviewing information that you have already learned/seen. It would be unreasonable to write out every commonly abbreviated term every time (e.g., gastroesophageal reflux disease, computed tomography scan, human papillomavirus, etc.). You raise a good point though, that it may be worth changing a few of the more definitional cards to include the written-out term. Those with the AMBOSS addon can hover over BUN to see the full term if they like
Perhaps there could be a preapproved list of acronyms that can be used without spelling them out in the card (“blood urea nitrogen (BUN)”). This would avoid ambiguity in reviewing contributions and if a new term is added to the approved list later on it’s easy to do a find and replace later on.