What is the rationale for this exemption and how is it interoperable?

757 A Client MAY process the Packet without checking the Properties by skipping over the number of bytes
758 specified by Property Length. A Client which does not check the Properties MUST NOT make use of any
759 Property it has not checked. A Server MUST check all Properties in a Control Packet.
760
761 Non normative comment
762 This exemption for Clients is designed to allow for simple Clients that do not require the
763 information sent in Properties. A full function Client should check and use the information in the
764 Properties.