There's no inconsistency, the "False" printed in your console is just the repr of the object, you can give that repr to your own object if you have nothing better to do with your life:

    >>> A()
    False
    >>> bool(A())
    True
    >>> type(A())
    <class '__main__.A'>

A repr is just a representation in development context, nothing more and nothing less, there is no requirement that it be sensible or of any use, though that's certainly recommended (contrary to __str__/__unicode__ which should be silly):

    >>> B()
    A gray parrot

The only "inconsistency" you've created is that False in the console's local namespace does not match __builtins__.False or the interpreter's internal False object. You can still access the former by the way:

    >>> False
    True
    >>> __builtins__.False
    False

unless you also override it:

    >>> __builtins__.False = True
    >>> __builtins__.False
    True

the interpreter still does not care though, you've just broken any Python code relying on the builtin (you can actually alter the "true" False object via ctypes)