Here's a parking notice for blue badge holders at a local authority car park.
Blue badge holders also have a blue card clock that sometimes needs to be displayed alongside the blue badge where blue bad parking has some time limit. Simple enough... set the cardboard hands on the cardboard clock to the parking arrival time.
This sign goes a step further. Rather than simply - as would be usual - ask for the clock to be displayed, ...here there's a rather different exacting tone here....that they "must be displayed correctly". That's all rather implicit in their use, and explicit in the instructions that come with the Blue badge.
