How would you know if the inherited hashCode is correct or not? Would you just assume that it isn't? That would result in lots of redundantly defined hashCode methods. Not sure that's better.
You could add two keywords like /notice/ and /keep/. If a parent class's function definition of foo has /notice bar/, overrides of foo could allow the new class to inherit bar with /keep bar/, or warn if neither a keep statement or an override are present.