When a player is choosing a school just for their baseball program, "transferring" may be more of a concern than a player who chooses a school for their academics and baseball. Fenway mentioned above that most HA schools don't have a turnover on their rosters. My son's HA D1 had players that realized they made the wrong baseball decision but most did not transfer and finished their degree. If they do transfer it was due to academics.
IMO, a player should not rush to commit to Big State U just so they can "boast and post". For my son when considering schools he focused on a school that if baseball has ended ( for what ever reason) would he want to stay at the school until graduation. This makes the "transfer" much less likely.
If the player is one of the few that has been identified as draftable out of high school then their decision process may be a little different. But most are not! As I have mentioned before " Players initially can choose the school they DREAMED/WANT to play at but eventually they probably will end up at the school they SHOULD of gone to.