This was happened on a single place among a select group of people (US diplomats and related, in Cuba). They could have talked to each other about the events as

This was happened on a single place among a select group of people (US diplomats and related, in Cuba). They could have talked to each other about the events as they were happening. I don't know what actually happened and details overall are scarce. The only thing I know is that ruling out psychological effects is difficult to rule out and the kind of argument you quote above has failed in other instances.