Jake Mangum was the Miss State player who signed for 20K out of the 4th round after senior year. The previous year he received a call from an organization offering 300K if they drafted him. He told them he was returning for senior year.
I don’t believe waiting until being 23 years old to come out is wise from a baseball standpoint. But his family is very well off. His father might have told him if he wanted to stay in school he would cover the loss. Mangum did pass on receiving scholarship money his last two seasons so there would be more money to sign other talent.