Binding conditions

Looking for where we set binding conditions, I see no specification of a 
restriction that MIPS are only applied to nodes with simpleContent.


I find this, under 
https://www.w3.org/community/xformsusers/wiki/XForms_2.0#Implementation_Requirements_Common_to_All_Controls



Controls that write simpleContent to instance data must do so as defined by 
the setvalue action 
<https://www.w3.org/community/xformsusers/wiki/XForms_2.0#The_setvalue_Element> 
.
Note: If a control binds to an element node, then regardless of how many 
child nodes the element has, the result of the control writing to it is 
that it has either a single non-empty text node child, or no children if 
the value written is the empty string.


However <bind/> is not a control. Also, that Note is rather odd, since is 
is non-normative, and I'm not sure where it draws its conclusion from, 
since in principle (I thought) it is not possible to write to element 
content with children.


Steven