If no files/mappers/layouts are open, closing Pro should not warn you about saving the workspace.
I just got through with two weeks of edits on a bunch of files in a workspace, packed all the tables I had edited and closed all the files. I went to close MapInfo and it asked me if I wanted to save the workspace. Considering there was nothing to save, and the danger of overwriting absolutely nothing onto an existing workspace, MapInfo should not put up a warning at all when there are no files, no mappers and no legends open.