The safe in the rooms at some hotels in Cayo Guillermo are operated by the same key as the room. This could lead to your wallet being slightly lighter than it was when you put it in at the beginning of your holiday, as you won't need it for the duration of the all-inclusive stay. Somewhat annoying if you choose to tip the cleaner and find out on the bus back to the airport!
talk
The local language is Spanish, but English is spoken in the hotels.