We are experiencing some behavior that we think is very strange.

Reproduce steps: 
* Create a new block somewhere in the "For All Sites" 
* Create a page "A" 
* Use the block in a content area on page "A" 
* Create a page "B" 
* Move the block used on page "A" inside the "For This Page" folder on page "B" 
* Delete page "B" 
* Run the Scheduled Job called "Remove Unrelated Content Assets" 
* The job will remove all blocks / images in "For This Page" for page "B" 
* The block is effectively removed from page "A" when running the "Remove Unrelated Content Assets" job

This is much better than the page crashing, but the behavior is quite strange. Why does EPiServer allow editors to move content used by page "A" into the folder "For This Page" on page "B" in the first place? It doesn't make any sense. That sounds like something that shouldn't be allowed to do. The scheduled job "Remove Unrelated Content Assets" will remove the block itself and from pages it was actually use.

What is the reasoning behind this? This sounds like a bug, as I can't think of any editors would want that to happen, and it's quite subtle.