One of the best examples of the use of a pretending layer to get people to pay attention is this from the US CDC - Centre for Disease Control.
They obviously have a hard job convincing people to plan ahead for bad news - who would read this in their free time?
So they thought to draw attention to ideas of preparedness by getting people to consider something they are more likely to have considered preparing for - a zombie attack.
It sounds odd - but just as lots of teenagers have given serious credence to falling in love with a vampire, so have many people considered what they would do should the dead rise and walk the earth.
The clever thing the CDC saw was the the cross-over. They they assembled official advice pertinent to more likely disasters - you can fantasize, but also earn something.
Like most stuff it is a Venn diagram.
You need that cross-over, where the concerns of the fictional world (infrastructural chaos and possible death) cross over with the real world (infrastructural chaos and possible death).
You want to mitigate against too much reality (antibiotic replenishment, urban evacuation) because it is (thankfully) so alien to people as to be irrelevant.
You also want to avoid the excesses of fiction ("pack a Ruger 10/22 for decent mid-range protection and light ammo") as it is too far from the core needs of practical advice and possibly nutty.
So pretend needs to tread a line of credibility - as they say "all the best lies have an element of truth".