But no early-entry candidate projected to go in the lottery has ever withdrawn from the draft.
Not one, according to the NBA.
So, while Wisconsin, Stanford and Duke all hold out hope that these four players will be on campus in the fall, the reality is that once each made their announcement, the chances were incredibly slim they would withdraw from the draft.
"Any time a kid is projected that highly we assume that they're going to stay in the draft," said one Western Conference scout. "We all assume that once Harris, Livingston, Deng and Childress declared that they would be staying in the draft. It sounds good to not hire an agent. But I doubt any of them would be playing in the NCAA next season."
Deng, who played one season at Duke, and Livingston, who was projected to be Chris Duhon's replacement at the point at Duke, are projected to go as high as No. 3 and No. 4, respectively, in the draft. Duke's staff made its plea to each before their announcements. Now that they have entered the draft process, the Blue Devils' staff isn't begging them to return.
Duke coaches knows it's simply out of their hands. They have made their case, but the financial security of being a top-five pick will likely outweigh the need of each to better themselves as basketball players or even as individuals for a year at Duke.
As Duke assistant coach Chris Collins said, the Blue Devils will hold their scholarships open. Duke will wait until June 17, the deadline for Deng to withdraw from the draft. Livingston has the same deadline to withdraw from the draft, but as a high school senior he could hold off his decision to go to Duke.
The Peoria Central point guard could wait until after the June 24 draft, even if he were selected. (High school seniors can be drafted and still go to college, but the NBA team owns their rights until a year after their eligibility expires. This rule went into play last year and no one tested it. No player is expected to do so again this season.)
So, if Livingston goes in the top five (as projected), it would make no sense to still to go to Duke and run the risk of an injury.
The prevailing opinion in the NBA is that players who are in the top 10, but say they're going to test the draft process, really aren't doing any such thing. The players who are borderline first-round picks (see: Saint Joseph's Delonte West or Mississippi State's Lawrence Roberts) are the ones who are truly going to test the draft process.
Unlike any of the high school seniors, or Childress, Harris or Deng, West and Roberts are expected to play in the Chicago pre-draft camp. They could move into the first round by playing well for four days in June and then continuing to produce in individual workouts. That would be testing the draft process and seeing if they could secure a first-round spot.
But projected lottery picks almost never play in the Chicago camp. They do participate in selected workouts for teams that are in the range of where they might be selected. Usually it's never past the first 13 picks (14 this season with the addition of Charlotte).
Childress is projected to fall anywhere from 6 to 11, depending on where teams fall in the lottery. For this reason, Stanford isn't holding its breath waiting for the junior swingman's return -- even though he put off a final decision by saying he wouldn't sign with an agent to protect his amateur status.
"You can't sit here and worry about whether he's going to come back," said Stanford assistant coach Tony Fuller. "I think they do that (say they're not going to sign with an agent) to cover themselves in case they fall off the board. He's worked his whole life to be in this position, and when it comes up we will support him and wish him luck. We know if he's in the lottery he's got to go. You can't turn your back on that kind of money."
Still, not signing with an agent comes with its own problems if a player decides to return to college. And the biggest negative is reimbursing the NBA teams for individual workouts. The Chicago pre-draft camp is covered under NCAA rules. Projected lottery selections like Harris, Deng and Childress will go to Chicago for the medical tests, but wouldn't have to reimburse the NBA for those expenses.
But, as Notre Dame's Chris Thomas found out, documenting all travel receipts for visits with teams is a must if the player is going to return to college. Thomas chose that route last spring instead of going to Chicago. Once he withdrew from the draft, he paid back his expenses and was eligible this past season at Notre Dame.
Al Jefferson is in a somewhat precarious position. The Arkansas signee out of Prentiss, Miss., said he would declare without signing with an agent. Jefferson is a borderline lottery pick with the potential to get into the top 14. But he could also slide down into the 20s. He hasn't signed with an agent, so if he chooses not to attend Chicago and instead work out for individual teams, he would have to pay for his travel expenses. He could try to convince NBA teams to come to Mississippi to watch him work out, but that would mean someone locally would have to set up the event.
Arkansas has been supportive of Jefferson's decision throughout the recruiting process. The Hogs aren't ruling out him coming to Arkansas yet because he hasn't been a lock for the lottery.
"If he's in the lottery, I expect him to stay in the draft and I've know that since last summer," Arkansas coach Stan Heath said. "If that happens then no one will be surprised if he stays in the draft. We've all been clear about that since day one."
So far, there are 20 players who have declared without yet hiring an agent. Of those players, Harris, Childress, Livingston and Deng are the only players who are considered locks for the lottery and expected to stay in the draft. High school seniors Jefferson, Robert Swift and J.R. Smith could play their way into the lottery, and wouldn't be expected to honor their commitments to Arkansas, USC and North Carolina, respectively.
But the anticipation at schools such as UCLA (Dijon Thompson), Mississippi State (Roberts), Saint Joseph's (West), Washington (Nate Robinson), Auburn (Marco Killingsworth), Charlotte (Martin Iti), DePaul (Dorell Wright) and LSU (Brandon Bass) is that their early-entry candidates will be on campus in the fall.
History says Harris, Deng, Livingston and Childress won't be.
But Wisconsin coach Bo Ryan isn't relying on history. He's still going to put his trust in Harris and the idea that the reigning Big Ten player of the year still doesn't know what to do and simply bought himself more time with his Wednesday announcement.
"I don't care that no one else has done it," Ryan said of a projected lottery pick withdrawing from the draft. "This is the way the system is set up. He has to declare by May 10 but doesn't have to sign with an agent. He is unique.
"I honestly believe he hasn't decided. He deserves the time to make his decision. It's not for me to be selfish and demand a decision for us. This is the way a person says, 'I'm not sure,' by declaring and not signing with an agent. Devin is just working within the system."
Andy Katz is a senior writer at ESPN.com.