There has been some confusion with some passengers thinking they have to pay for an expensive excursion or they won't be allowed to go ashore in Cuba. This is false and the following provides the official rules.Thanks to rederob/justRobme for finding this info.
This link decribes the process for guests who wish to go ashore and tour Cuba:
and this link is to the certification form:
Thanks for posting Spunky and to Rob for the research-very helpful!