You're wrong, it is returned — and if it wasn't, the code wouldn't reach here as it's checked when parsed from the document:

```
> db.runCommand( { parallelCollectionScan: "test", numCursors: 5 } );
{
	"cursors" : [
		{
			"cursor" : {
				"firstBatch" : [ ],
				"ns" : "test.test",
				"id" : NumberLong("177116090964")
			},
			"ok" : true
		}
	],
	"ok" : 1
}
```