The reverse, f(*(1, 2, 3), foo=4), is consistent with 
f(1,2,3, foo=4)
who also gave 
TypeError: f() got multiple values for keyword argument 'foo'

Which is consistent with the tutorial
http://docs.python.org/tutorial/controlflow.html#keyword-arguments

def parrot(voltage, state='a stiff', action='voom', type='Norwegian Blue'):
...
but the following calls would all be invalid:
parrot(voltage=5.0, 'dead')  # non-keyword argument following keyword
parrot(110, voltage=220)     # duplicate value for argument