Even if it's from a social network, you still can't be sure. Especially, if a photo have multiple persons.
" The system found a match in the background of some photo taken at a trade show (the guy was working a both). It only knew the website the photo was from, which allowed the police the identify the trade show, which allowed them to track down the people working at that booth to find their suspect."
With that said: the order is clearly impossible to execute. There's a huge difference between police clicking on a URL in a result and manually investigating to determine the location and having their system automatically determine the location of all photos and delete the ones that are in Canada.
It is clearly possible to execute, it would just require much higher costs per image that ClearView processes and the probable need for ClearView to avoid using any images that they can't verify the location of in am economical fashion.
Saying it is "impossible" is different from saying that the costs of compliance would fundamentally change ClearView's business model.
You don't need the Internet or AI to collate pictures and the data on them into a database.
If the answer is 100%, then yes, all user-generated content on the internet will have to be banned unless subject to manual human review before allowing the post to be seen, and even that is probably not perfect.