Well, obviously everyone would have to know:
1) To bump spam to the bottom (or off) of the page
2) If you see everything has been bumped then that must mean there's a piece of spam at the bottom or just off the page.
Once that's established THEN the mods will know when and how to find Spam. But since it isn't a normal thing now 'days then ofcourse they don't know how to find the Spam. How do you know to look both ways before crossing the street? It's not like humans are born with that knowledge. You need some teaching and experience to learn to look both ways. That doesn't mean people can't LEARN to look both ways.