DOM L3 Core and L&S Comment/Question

RE: "format-pretty-print" feature (for DOMWriter)

Currently the specification is not very clear on what this feature may do 
and does not define the transformation so implementations can presumably 
do what they want.

I was wondering if the working group had any thoughts on implemenations of 
writers having to maintaining validity when this feature is switched on. 
Does the DOMWriter implementation have to maintain document validity when 
this feature is switched on?

In my mind the implication is no because the spec implies a transformation 
occurs which in turn implies validity may not be maintained with any 
DTD/Schema associated with the document.  Also maintaining validity with 
any DTD/Schema makes the writing process complicated if the feature is 
switched on.

Any thoughts/comments?

Perhaps the specification could be altered to make it clear whether or not 
an implementation has to maintain validity.
Also, should setting the "format-pretty-print" switch of features such as 
"validate"?

Thanks.