Take these signs, for instance, from my trip to California in October.
A trained soothsayer would take one look at these and know immediately that they shout out: Danger! Beware! You were exposed to the flu on your flight across the continent, thanks to the person in the row behind you, and it will make itself known to you in about six more hours!
Sadly, I am not trained in the saying of sooth, and had to learn of their warning the hard way.