Yes, I agree with both of the above. Cuba is not a particularly dangerous place and you are not more likely to get robbed there than anywhere else. Just take the usual sorts of precautions and all should be fine. Having said that, the second time I was there my wife had a camera robbed in Havana one night. We were walking home from a baseball game (!), at night, lost, with no idea where we were. We were actually chatting with two American friends we had met about how, in almost any other city in the world, one would tend to be slightly concerned and on edge in such a situation, but not in Havana. Next thing, this young lad appears, grabs my wife's bag off her shoulder, leaps onto the back carrier of his accomplice's bicycle, and tears off down the road.
We were a bit stunned obviously, but it was followed by the people who lived on the street coming out to see what the commotion was, insisting on bringing us into their house, phoning the police, giving us tea, organising a taxi to get us back to our hotel and so on.
So, I suppose the moral of the story is ... don't wander completely aimlessly at night, in darkened parts of the city, where you don't know where you are, with a handbag hanging over your shoulder. But you knew that already, right ;-)
I am envious ... both of my trips to Cuba happened before I got seriously interested in photography. I'm itching to go back!
There's another thread about Cuba by the way somewhere in this forum ...