What are the implications of not having UN Number associated to Hazard Class?

Summary:

In Manage UN Numbers task, we see that Hazard Class is not mandatory.

What are implications of having and not having Hazard Class associated to UN Numbers?

Content (required):

Our client has UN Numbers being shared across Hazard Classes i.e. a UN Number could be associated to 2 Hazard Classes.

To configure this we are creating 2 records for same UN Number associated to 2 Hazard Classes.

The issue is that the combination of UN Number and description has to be unique.

But we dont have different description.

To tackle this, we are exploring what if we dont associate Hazard Class at all and have one single record for the UN Number which would be used in Item Master