If a player is on the continent they have to go through the draft. However, if the player manages to get to a Caribbean island like say, Dominica they are free agents. Look for these kids to be on a one way plane to a country that doesn't require a passport (since Cuban official take them from the players).
Defection fun fact: Mariners shortstop
Yuniesky Betancourt defected during the 2000 World Championships in Edmonton.