Why hide it completely? What about exposing your interface by convention like in Python? Never heard anyone suffering from inability to make methods and fields private in Python.
Edit: Why not make all variables global? Why not just use convention to label a globally scoped variable as "global" or as "local"? You can make it work as a convention. Now apply that to the whole language and to all the developers ever use it.
Why not make everything global? For obvious reasons - modularity, memory consumption, and inconvenience of lengthy variables names.
For example I use your library and everything goes great until I'm stuck because I need to have an information hidden in a private field, if I'm in Python I would do it and add a note, fixme, todo, whatever that this is a hack and things may break in a future, but my code would work right now. And I can fork your library later and submit changes. If this is a language with real private support the only way is to use hacks (reflection) which is the same as using the field directly like in python just with some additional PITA, or to fork your library and maintain it until you merge changes, or if you not, I have to maintain it forever.