I stand corrected, at least regarding Acosta and Carreno, who apparently do return to perform at the Havana Ballet Festival. Here is another link that confirms it – note the word “legally” and the fact that Acosta acknowledges that he got an education in Cuba he would have been unlikely to get elsewhere.
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http://www.cubatravelusa.com/ballet_cuba.htm
Stars like Acosta and Carreno, who earns up to $10,000 for a one-night gala appearance, recognize their debt to Cuba. Most left legally and maintain ties to the homeland, returning to perform at the Havana Ballet Festival every two years.
“Classical training is very expensive in other countries. I come from a poor family and had the good fortune to go to ballet school in Cuba,” said Carreno.
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[off topic remarks deleted]