P & O Orient Liners of the 1950s and 1960s

An insight from P&O "90 percent of all P&O bookings are done by two adults that are looking for one cabin, so the option for one cabin was automatically selected to shorten the process. The 10 percent of visitors for which this was not a good fit could change the option and choose a more suitable accommodation when checking out." This sounds like the Nudge effect where companies enroll employees into 401k by default. You must have come across organ donation which worked when people had to opt out of it rather than have to opt in, if interested.