Luddite, I'm sorry, I completely missed your post until I saw you mention it in your question about debarkation time.
I think the mention of lectures and cooking demonstrations were just examples. I don't think you will find out the specifics until you board.
To be honest, I don't know what Berlitz is talking about; and I don't think they do either; or it's a misprint: there are only two cabins on Dolphin deck, the two Family Suites all the way forward, that have privacy; all the rest of the balconies are open to the three decks above. The balconies on Caribe deck are half covered, half esposed; you can have privacy by sitting back by the balcony door.
I have had Dolphin Deck cabins several times and privacy has never been an issue (of course we don't sunbathe in the nude); the passengers above have always been very respectful.