There are so many updates to InDesign these days and I have so many files it's guaranteed that most of my files will now be in the "previous" version so I get them all opening as "[Converted]". Most of the time I just open them to refer to things, so it's annoying when you close it and it asks you if you want to save it even though you haven't done anything.

Like any other document, ID should know if you've made any changes. If you haven't, it should just close the document without prompting you to save it.