What is the rationale for requiring dfdl:encoding on the xs:sequence element?

[Costello, Roger L.]

Hi Folks,

If I omit dfdl:encoding from the xs:sequence element, I get this error message:

[error] Schema Definition Error: Property encoding is not defined.

I struggle to understand the purpose of specifying an encoding on xs:sequence. 
Would you explain the rationale for this, please? As far as I can tell, the 
DFDL specification doesn't require encoding on xs:sequence.

/Roger