I can't think of a time we would call either of these methods without asking the user via a file dialog now (especially given that from now on we will make sure all file access is granted through drag an drop or a file dialog for OS X). 

Though this reminds me I forgot to deal with upgrading from a single-library Mixxx but that code touches DirectoryDAO directly!

I thought it made sense to not duplicate it everywhere and risk forgetting a spot. Also, if someone in the future adds a call to this method they don't have to remember to also create a sandbox token. If they didn't do it via a a file dialog (naughty!) then it'll silently fail.