Pikey
Dummy Ejection Facilitator..
I'd guess this sort of thing is illegal Equisafety Polite Air Road Safety Fluorescent Waistcoat: Amazon.co.uk: Clothing
If it's not meant to warn with the idea of impersonating a police officer then why the blue 7 white checks and why have the word polite?
Cos it was designed by a chief constable an approved by MOJ & ACPO. to try and cut down on number of injuries and deaths amongst Horse riders.