P: Collections Library Filter

To test my understanding, you'd like to see the ability to do this query in the Library Filter bar:

Text: Collections Doesn't Contain <name of collection>

to find all photos that aren't in <collection>.  

Another workaround (also not ideal), which works better than smart collections when you want to filter another folder or collection for photos not in the collection:

1. Select the collection in the Collections panel.

2. Select all photos in the collection.

3. Click the folder(s) or All Photographs, whichever source(s) you want to search.  All the photos in the collection remain selected.

4. Do the menu command Edit > Invert Selection.  All the photos in that source that aren't in the collection are now selected.

5. Add the selected photos to the quick collection.

This would be helpful for me to see photos that are not added to a specific collection or any collection at all (and should be).

Heres an example of my workflow where this would be helpful: I take photos daily of various projects and then add them to collections based on the specific project. Sometimes, this doesn't happen due to time, forgetting, having them imported in the field through CC on Ipad, etc. So down the road when I go to edit a specific project and look at them through the Collection I often times end up missing photos that never got added. I find that I quite often am right clicking on photos in my daily usage just to make sure I have them added to a collection when I come across them in the catalog. 

You can restrict the currently filtered photos to one or more collections by selecting them in the Collections panel. How would adding "Collections" to the Library Filter Text bar or the Metadata browser improve on that?