nob-rels (you asked for a better name 😊), called "no object relationship" will do *exactly* the same as acs-rels, but not create an acs object. Therefore it will link any object to any other object.
You have a valid point with regards to permissions and though we do not need it (folder permission is enough) it might be better to use acs-rels or content-symlinks if we want to make a general solution. Though, wouldn't folder permission be enough in general (after all you just create a symlink in that folder so the users that have access to the folder can see the file). One benefits of using content-symlinks comes from the fact that we would not have to modify the folder-chunck queries (at least in theory) as content-symlinks are cr-items.
Nevertheless I think nob-rels is a good idea e.g. in the assessment example or application-(data-)links.
We expect around 1,5 million other objects per year, partialy due to the application-(data-)links.
