Carnival's new business model is to fill the ships at all costs - and soak them for as much as you can get once they get onboard. Drinks, bingo, photos, I've noticed the selling is much stronger than before.
Still possible to get off the ship with a $0 balance? Sure!
At least on Sunshine (the ship I have most recent experience with) they'll typically do one evening where the comedians are in the Liquid lounge and the night club moves to the Limelight.
Of all the ships, Sunshine is the one that really should have comedy in the main lounge full-time because that ship's Limelight lounge is horrible.
I’ve talked to some of the comedians who say they like the smaller more intimate setting of the Punchliner. They can more easily see and hear the audience.
You should see how much food is wasted in the galley that never even reaches guests! Hopefully they've gotten better but yes there is a lot of fish food being made.
I wonder how many thousands of photos they printed on your cruise, simply to throw them away as well?
Yes they do show movies on the stateroom TV every cruise, all cruise long, but those are typically older movies. The dive-in movies are usually more recent releases, maybe last year's blockbusters etc.
In general you are not allowed. Enforcement obviously varies. I have seen guests be made to pour out drinks before they can get off the ship, or get back on the ship, before.
Sealed drinks are fine - this is what my wife and I use our large bottles of water as returning guests for.