Ten years after turning the Giants down, Castro had overthrown Cuba's U.S.-backed government and was ruling the country himself. As we mentioned, he was already into Marxism while in college, but seriously, who wasn't? The main difference is that instead of putting Che Guevara on his T-shirts, Castro actually went on to hang out with the guy.
Our point being: There's a chance Castro would have said yes. Without him, or with a leader who was less charismatic, less stubborn and less impossible to kill, the Cuban Revolution would have failed and the Cold War would have unfolded differently. Keep in mind that the closest the world has come to a nuclear war happened when the Soviets thought it would be a good idea to put missiles in Castro's Cuba. In fact, some have pointed out that the successful resolution of the Cuban Missile Crisis is what emboldened the U.S. to jump into the Vietnam War.
"We're on a roll; what's the worst that could happen?"