The statement a role uses to express a grant can be any property, including one from another vocabulary. The network then needs to know which side of the statement is the space and which the person, and it only knows that for a fixed set of common properties. For any other, a grant must carry that information itself, or it is silently ignored — it never reaches the space page, and nothing reports why.

A role's assignment template takes care of this: it records the direction in the template, and every grant made through it carries the note along. Grants written by hand need to include it explicitly.