The idea comes from teaching projections and transformations to so many students and not wanting them to continue to mess it up in the future. When you first add a layer to the data fram it attaches a projection coordinate to the frame which is all well and good. However, when you add a new shapefile, or feature class, that is in a separate projection or geographic coordinate, it will allow the file to be "projected on the fly". All well and good for this, but at this point, you then have to open up the tool to change the projection from projections and transformations, or run the search and get the project tool, or define project tool. Is there a function that could be added to that first geographic coordinate WARNING pop-up that tells us that it will project the image, but "alignment and accuracy problems will occur unless there is a correct transformation between geographich coordinate systems" (Warning box). What the idea is, would be to have this same type of GUI pop-up and be able to click a toggle button to only "Project on the Fly" or "Run Projection transformation now" and be able to select from favorites. Then a separate toggle do this for all items I place in current data frame. I know this is just another way to be lazy, but projections have caused numerous problems in the past when people get part way through and then look at the data they were messing with and low and behold, the projection was never changed. Now, all the work they did has to be scrapped and changed properly through the projections and transformations or there will be alignment and accuracy errors. Not sure if you will be able to do this, but please take it into consideration.