PDFs have the ability to mark layers as non-printing, so that they appear visible on the screen but don't print to hard copy. I'm using this capability to add a light raster background to all pages of a workbook for students, which adds a bit of warm color to the on-screen viewing experience, but I don't want this background to use up all their toner if they decide to print the pages. Similarly, the entire workbook has page numbers, but the worksheets should print without the page numbers, because they're not relevant outside the context of the book.

I found a solution thanks to helpful advice on Reddit (https://www.reddit.com/r/indesign/comments/191ojvr/creating_a_pdf_with_visible_objects_that_do_not/), but the solution requires changing settings in the PDF after the export, which means that you have to redo it every time. It might be preferable to have an option on the layer options within InDesign, or a set of options in the export dialogue that can be saved as part of the preset. Not only would this make for a more comfortable user experience, but it would also save a lot of hassle figuring out how to do this in the first place, because it's not obvious that there wouldn't be a way to do it in InDesign and many things look like they would work until you try them.

I've included an excerpt from the PDF to show how the result works and to better communicate how such a feature would be useful.