Section 9: should non-public enum constants follow the same private instead protected rule as methods?

[rodrigoprimo]

Section 9 requires non-public enum methods to use private instead of protected:

Non-public methods MUST use private instead of protected, as enums do not support inheritance.

It states nothing equivalent for constants, yet enum constants can be non-public, and protected const is valid. The same rationale applies to constants.

Is there a reason for this I'm missing, or should the rule be updated to apply to non-public enum constants as well?