People tend to habituate and take little notice of announcements which are frequently repeated. You only need to watch the antics of air stewardesses telling frequent fliers about lifesaving emergency procedures -and being studiously ignored.
This phenomenon is even move noticeable when it comes to recorded announcements on the railways. It’s perfectly possible to hear an automated announcement of which n stations a train is about to visit, n times in the course of a journey.
Today’s invention is simply to persist with oft-repeated messages but to have each recorded by a variety of different, engaging voices saying the material with slightly different phrasing. In this way, a higher level of attention can be generated for each announcement.
As long as the diction was clear, regional accents or a heightened emotional note might be used to good effect -especially if a warning was involved. Each message might vary randomly in tone from start to finish in order to keep people cognitively ‘tuned in’.