Over the years I have come to the conclusion when working with switch statements that switches on enum values, a DEFAULT block MUST be required.  Not only should it be required, I think it should throw a developer exception.

*** NOTE ***
My stance on this is ONLY in scenarios where the switch statement is the primary pathway.  If the switch is for secondary actions, this may not be needed.
*** NOTE ***

Too many times odd/weird bugs have cropped up in code because a new enum value was added to the enum  and the switch block did not handle it correctly and the code get all fooed up.

Why should it be required?

• Enforces tight code
  How does it enforce tight code, but failing if all conditions are not met.   By adding the default block,  all new enums values will be handled and an exception will be thrown.  This exception will notify the developer that a new case needs to be taken into account.
  

•  Makes the developers immediately aware of changes that may affect their code
  By adding the default block developers will immediately become aware when a new enum value is added.  This should be caught early on and handled, so in reality it SHOULD never be exposed in production.

Possible scenarios where this should NOT be required

• When there is already a default statement in used for business reasons
  If the case statement already has a default block for some valid business reason, then of course you cannot have it throw an exception.
  

• When the switch statement is NOT the primary pathway.
  If the switch statement only performs secondary actions, there may not be a need to have the default block.  You should look at this closely….
  
  

Enum Defined

Usage 1 – Wrong in my opinion

Usage 2 – Correct in my opinion

The point of this post is to get you to code for failures in order to succeed.  You may not agree with my stance, but I bet if you give it a try you will find you will have less errors when enum values are added and you will be happier in the long run.