[narvind]

Just to take away the creepiness factor, I'd say things like: Passengers who shared their favorite drinks with us rate us higher because we know them better and serve them accordingly.

This is akin to amazon's main website changing "We recommend the following to you" to: "People who bought this also bought" - to induce a subtle hint of jealousy that others are getting a better deal and this is totally optional.

Any recommendation system should be a voluntary opt-in feature and should consistently do a great job at recommending.