Only plaintext Attributes in AttributeQuery

Hello SAML Devs,

While studying the documentation and the xml schemas, I noticed that an
AttributeStatement allows to use Attribute- or EncryptedAttribute-elements
(or both) as children. An AttributeQuery in contrast allows only plaintext
Attribute-elements.

I wonder if this serves a specific purpose or if
EncryptedAttribute-elements were just simply forgotten in this context. It
would make sense for me to have an opportunity to encrypt Attributes in a
query. Are there any protocols that require Attributes in AttributeQueries
to be sent in plaintext?

- Dennis Felsch