I seem to remember Devin Jones and Nick Routt wanting to transfer rumors. Those turned out to not be true.
With the rules in place- it's usually better to stay at the school you are at. Whether the rules are right or wrong, that's how it works.
Like Trey Johnson for example- if he tranferred, he is going to have to go somewhere like Delta State. The fact of the matter is this- all of these players, except for some of the walk-ons are pro prospects. Most of them want to at least get into pro ball. Your chances are a lot better of playing professionally if you play at MSU vs Delta State because of the level of competition, and more importantly you can make more money. It's because of the conference we are in- the SEC is somewhere between high A ball and AA most years because we have a few players that move pretty quickly every year to MLB- like Pedro Alvarez, Luke Hochever, David Price, and etc. not to mention all of the other players that usually have solid pro careers.
Believe me, players think about that and weigh that before they make the move, because once you leave, you can't come back unless you go JUCO, and even then it is very unusual to come back.