DMN17 — DRG requirements only state am unused knowledge requirement is illegal

Subsection "6.2.2.2 Knowledge Requirement notation" of "6.2.2 DRD Requirements" states that knowledge requirements must be utilised in the decision/BKM knowledge requirement:

"If e is a decision or a BKM in some DRD, and e contains a knowledge requirement on some invocable element b, then the logic of e must contain an invocation expression of b, including expressions for each of b's parameters."

However, this section does not mandate that Information Requirements must also be utilised by the requiring DRG element in the same way that a knowledge requirement must. If a purpose of DMN is to serve as documentation and show actual relationships between decision elements then it is paramount the DRG reflects actual usage in the model, otherwise the graph is incorrect - it may show relationships that do not reflect the decision-making reality.

I propose adding the following to section "6.2.2.1 Information Requirement notation":

"If e is a DRG element in some DRD, and e contains an information requirement on some other DRG element b, then the logic of e MUST contain a usage of the information provided by b"