  A so called 'weak value' of an observable in quantum mechanics (QM) may be
obtained in a weak measurement + post-selection procedure on the QM system
under study. Applied to number operators, it has been invoked in revisiting
some QM paradoxes (e.g., the so called Three Box paradox and Hardy s paradox).
This requires the weak value to be interpreted as a bona fide property of the
system considered, a par with entities like operator mean values and
eigenvalues. I question such an interpretation; it has no support in the basic
axioms of quantum mechanics and it leads to unreasonable results in concrete
situations.
