Section 4.1.8 in RFC 2251states:
"(Though attributes MUST have at least one value when stored, due to access control restrictions the set may be empty when transferred in protocol. This is described in section 4.5.2, concerning the PartialAttributeList type.)"
This section as well as 4.5.2 don't make a distinction between "transferred in protocol" and "transferred by the server to the client" implying that its allowable for a client to send an attribute with no values. There is surrounding language that implies that this case is specific to server emissions. Should there be explicit language?