No, not impersonating the police (that would be illegal), but you have to wonder about the choice of the word "POLITE" - its a bit of a random word to have written on your back... If i was about safety, they would have something more appropriate written on their backs such as "SLOW DOWN" or "THINK BIKE", but they dont... they pick seemingly random word. So is this a coincidence that at a glance, their seemingly random, unrelated word just happens to look like the word "POLICE"? no of course not! Wearing a "POLITE" jacket is not about safety, its a deliberate attempt to mislead other road users into mistaking the wearer for the police.