Hmm, revisiting the code, it seems I mainly used the modification dates against folders for consistency with the way files were cached. The problem is less that they are needed for any comparison and more that the cached database file saves folder names against the dates. I should just be able to use any date for folders without it causing any problems, I think.
We love to learn from the educators who use Dropbox. Whether you teach kids, teens, adults or a combination of all three, we want to know what apps and integrations you use with Dropbox to help with teaching. Which of the ones below is your favorite, or most used tool?