Did I understand correctly, the fact that the variable is not belonging to the closure is the non-intuitive part, not knowing "how it was decided to do in Python" I'd expect the variable to belong to the closure, but instead just the reference to the variable outside of the closure belongs to the closure? Which AFAIK doesn't save any memory (the reference still has to be there), it was simply a design decision?
So in Python the closure just doesn't "enclose" the variables at all? So any use of any variable in it can destroy something used "outside"? How do those using these construct cope with that in practice? Just ignore? Invent some naming schemes? Something else?
Reminds me on an old Fortran which allowed changing the global constants passed to the functions via an assignment to the function parameter inside of the function. :)