Something I just considered: For everyone saying "how does this even happen?"
These are players going in the 600-700 pick range.
Your draft board shows you 500. For anyone who says "show me my whole draft board", 20 million buys you 500 prospects in College Scouting. If you spend less, you'll get some (or more) ??? prospects. If you spend 20 million HS scouting you'll get 200-250 ??? prospects. So in this regard yes I would agree that seems to limit those who spend 20 mil on College... you're probably not going to draft a ??? unless you open up those bottom rounds of the draft.
Held a draft yesterday and in the 25th round, pick 805, I got the 374th rated prospect out of my 500. Now of course I never even looked at that guy, but what it tells me that if he was still that high on my board that other owners had combinations of rankings which were passing him over 10, 15, 20 times.
Depending on how your draft falls, your 374th guy - who you'll never look at - could slide right to the end. OR, he could go somewhere around 600 - considering that say half the other owners are budgeting "opposite" to you - in which case maybe you start getting those ???.
Point being, it's not just the rankings. First, we all see different rankings. Second, we set up our draft boards entirely individually - not just the rankings, factor in the position thresholds and the signability factors. NOW, you throw in just one of these Unseen Studs, I can see how it would be completely random where he ends up.
I can also begin to see how you could set up a draft board to try to mine one of these players. Some added effort for something that might not even be there. So you could decide if it's worth the effort.