I've an ItemType "Source" and a NULL relation.
After promoting ItemType "Source "to "Validated" an permission is set to disable Deletion :It works fine !
But, In the TOC, I can access to ItemType NULL relation.
After testing, I can remove item in NULL relation although the deletion on ITEM source is not possible.
On NULL relation, the permission seems to be good (the same as Source) !
Do you have a proposable to disable DELETE on NULL relation ?