> If the empty state thing was in reference to smart pointers, it'd be a remarkable misunderstanding of how they work and how they should be used.

No, I don't think so. Many C++ libraries, especially those originally developed before C++11, implement their own smart pointer templates, which may end up having diverging semantics. That's exactly what OP was describing.

Examples off the top of my head include: CEF, Chromium, v8, Qt, glibmm, and the internal codebase where I work.