That's not necessarily true. It's easy to build an app where you prompt for the user's text input to construct a filename for saving a document/picture for example. NSDocumentDirectory is very much still the recommended place to store persistent user data on iOS. Imagine any non-English speaking person entering a non-ascii name for their document.
As another example, imagine Dropbox.app syncing files from the dropbox cloud reusing explicit filenames into the app's sandboxed Application Support/Library/Documents folders. I have no if they do this but if they do this could spell trouble.
Or simply any app supporting iTunes File Sharing, allowing users to drag files from their mac into the app container's NSDocumentDirectory directly.
Edit: Interested in hearing counterarguments instead of downvotes, thanks? :-/
As another example, imagine Dropbox.app syncing files from the dropbox cloud reusing explicit filenames into the app's sandboxed Application Support/Library/Documents folders. I have no if they do this but if they do this could spell trouble.
Or simply any app supporting iTunes File Sharing, allowing users to drag files from their mac into the app container's NSDocumentDirectory directly.
Edit: Interested in hearing counterarguments instead of downvotes, thanks? :-/