There is a loophole in the US but AFAIK it is not abused. On several occasions I had breakfast with a bunch of "cops" that were actually active duty and reserv

There is a loophole in the US but AFAIK it is not abused. On several occasions I had breakfast with a bunch of "cops" that were actually active duty and reservist army. Their police patches were from all over the US and they wore high rank and high tenure patches on their sleeves. Every year they train as civilian police in the event of a major disaster that requires the federal government - DoD to take control and coordination of the police. This is done in coordination with the police departments their uniforms represent.