Default warehouse by Item

In item maintenance, each individual item can have a default warehouse code, however it does not seem to actually do anything.

 

If in purchase order or sales order,  the default warehouse code by item appears to be entirely ignored. 

 

The knowledgebase shows an enhancement request for both sales order and purchase order to actually honor the default warehouse code by item.

 

So if the system doesn't use the field in these areas,  where does it actually get used?