Cubas is a sports agent, the Don King of baseball. He had gone to Mexico to watch the Cuban national baseball team play a friendly game. As always, the team was chaperoned by a posse of Cuban security police to ensure no one defected.
His plan was to meet one of the team, William Ortega, in the toilet, urge him to leave Cuba and make serious money for both of them. But every time Ortega went to the toilet, a security man went along. Cubas could only whisper: "Meet me in the cemetery at midnight."
Ortega turned up with two team-mates. Cubas emerged from behind a tombstone, spirited them into his car, across Mexico and into the US, where all three now play pro baseball.
None of the "graveyard trio" has made it really big, but all earn many times the pounds 1.50 a week they were paid at home to play in their national team, recognised as the best in the world.
The cemetery story made 37-year-old Cubas a legend, but he has earned far more from other Cuban players. Take Livan Hernandez, who fled on a raft from Cuba two years ago, while still a teenager. Cubas got Hernandez a $4.5m (pounds 2.7m) contract as a pitcher for the Florida Marlins. The agent netted $250,000.
Fidel Castro, a baseball lover, calls Cubas a "vulture and flesh-peddler". He has accused the agent of stalking players on the island, which Cubas denies. But his cousin, Juan Hernandez, was sentenced to 15 years in jail in Cuba for trying to get baseball players out. "Harassing, bribing and corrupting Cuban sportsmen," was the charge.
Cubas says he assists players only after they have left, but few believe him. While most Cuban defectors flee on a raft, Cubas's clients tend to come ashore in the Bahamas on real boats.
The agent believes the Cuban regime would like to see him dead, and that his phone is tapped by Castro's spies. He says he receives regular death threats: "We're going to cut your legs off," was one anonymous message.
Cubas admits he lives in fear of his children being kidnapped. He is ex-directory and passionate about keeping the names of his family out of the newspapers. Once, he says, Castro "agents" went after a cousin who resembles him, in New York, beating him up with baseball bats.
His most recent client was Orlando "El Duque" (The Duke) Hernandez, half- brother of the Marlins' pitcher Livan, and a legend for his 90mph fastball. The Duke defected just before Christmas, taking a leaky boat to the Bahamas and then flying on to Costa Rica on a jet that just happened to have been hired by Cubas. He signed for the New York Yankees for $6m: that meant $300,000 for Cubas.