I have to disagree here.
Keyword arguments may be completely independent from the positional arguments of the same function/method. There is no special reason to make them dependent of the remaining positional arguments if this is not the case.
Many times the default of a keyword argument is just an instance of some object representing a safe default, and if this (often immutable) object is used in other places, then it is common for it to be stored in a global constant (for both the “no magical numbers” pattern and ease of change of the value in all contexts with a new release version).