There's another flavor under discussion: "Pay to Stay"
If a player goes to College they are eligible for the draft each year but must stay 3 years in College and leave in good standing to get the guaranteed contract. Otherwise, their rights are maintained by the team and all they have is the second round rookie minimum as a guarantee if they leave before 3 years.
In other words a Lamb or Drummond could be drafted this year and leave college for the second round rookie minimum or be drafted, finish 3 years at UConn (without recieving any NBA money) and then get their guaranteed Lotto contract after the 3rd year. That's the "pay to stay" option. Financially it's structured to blow away the "leave early" option.
This flavor might be coupled with High School entry. If a HS player gets a Lotto contract and goes straight to the NBA they get the usual deal. If not Lotto they will be encouraged to go to College and the team retains the rights.
18 High School Players Drafted Lottery. It's difficult to argue that it was the wrong decision for them. some were not superstars but they all made NBA careers. Robert Swift is an interesting story: would he have blown out his ACL in college and never had an NBA career?
Brown, Kwame
James, LeBron
Howard, Dwight
Chandler, TysonT
Miles, Darius
Curry, Eddy
Livingston, Shaun
Bender, Jonathan
Dawkins, Darryl
Garnett, Kevin
Webster, Martell
Diop, DeSagana
Stoudemire, Amar'e
McGrady, Tracy
Bynum, Andrew
Swift, Robert
Bryant, Kobe
Telfair, Sebastian