[TUHS] History of chown semantics

Sorry if this is off-topic but I bet someone here will know. I recently had a significant surprise when I discovered that on HP-UX ordinary users can still give away files. Various of us who remember fairly old Unixes then sat around trying to remember which systems had this and where it came from: getting it almost entirely wrong, it turns out. What we remembered was that it came from BSD, but this seems to be entirely wrong. It looks like it originated with System III / V, and perhaps was imported from there into some SunOS (possibly it was in all versions before Solaris?) which is why we remember it as being in BSD. It must have been in some 80s system or we would not remember it. POSIX still allows it but clearly reluctantly. So the questions are: (a) did it originate in System III or does it go back further than that, and (b) was it in the BSD-derived SunOSes or are we just making that up? And I guess: who thought this was a good idea? Thanks --tim