The acceptUnknown element is very awkward and therefore leads to misunderstanding.

1. It is unclear how a 'requirements' based CapabilityStatement should use this element. As in this mode the Implementation Guide is not declaring anything for the application, but rather setting 'some' requirements for the actor. — Might this not be required for requirements based CapabilityStatement?

2. Given the element name is itself a negative (unknown), and has a positive verb (accept); this makes it hard to understand the meaning of the element.

3. The vocabulary bound to the element are equally hard to understand from a language perspective, especially related to the element name.

4. The definition of "accept" is unclear. Does accept mean that no error will be thrown? Meaning is it acceptance if one discards the unknown information?

Should this element be required, or just recommended?