Private variables are not a security mechanism. They are communication between the class designer and client about what parts of a class are the user interface and which are implementation details. I’m not aware of any language than runs in user-space that truly “protects” private variables. I’m pretty sure C++ inventor Stroustrup explicitly stated this somewhere and Perl’s Larry Wall says something to the effect ‘I expect you won’t acces private variables because you’re a respectful person, not because I’m standing in the living room with a shotgun.’
So my feedback is that this goal is misguided, and prior discussion Private, protected modifier and __ notation indicates it’s unlikely to get community support.