Terry, it is interesting that BOTH Revit and AutoCAD MEP use sanitary tees in lieu of tee-wyes or combos for the default sanitary connections of horizontal to horizontal sanitary piping.
They may believe that they are too smart to ask questions. I deal with this all the time when I'm with engineers. They love to tell me
"My wife told me that is sounded like a good idea to her."
Yeah, well buddy, most of us in construction business prefer to ask someone "doing" the work, and not whoever is at the dinner table that night.
Another good one is the self employed handyman that is running solo without any thing to go by or any knowledgeable person to ask questions of. I've seen some God Awful stuff at times from them. One was at a church I used to attend. This guy was building a water wall in the main lobby. I saw how he was doing it and tried to explain what he was doing wrong. He shut me down real quick on that. When I went back, and asked why the water wall wan't being used as planned, I was told there was water all over the place and they just left it as a "dry" feature.
I'm sure the handyman figured it was just bad luck somehow.
For a cad program to auto correct the fittings in a layout it would need a lot of AI.
For us, it also depends on the fixture being served, not just the fitting.