When sharing a collection in DAM, potentially the other person cannot see all of the shared assets due to permission restrictions. Today, there is not easy way for the creator of the collection to determine this. This feature on a collection assets overview page (or even on any search result overview page?), could allow you to select another user in the system. The tiles in that result page, would then show an indication of what assets would be invisible for that other person (e.g. using an overlay icon or by showing the mosaic tile grayed out).
Customer support service by UserEcho