Cruise lines are racing toward hyper-personalised travel, and by 2030 the technology behind it will be hard to escape, from cabins that learn your habits to itineraries built around your data. The pitch is convenience: less waiting, service tuned to each passenger. But there is a trade-off nobody likes to raise over dinner. All that personalisation means handing over large amounts of personal information to companies that profit from it. Passengers may get the smooth sailing they want and give up more than they realise to get it.