When I first got the exemption to ride around doing deliveries, I had the certificate in my pocket, but clearly that was a time waster. I now have it stuck to the windshield and I've also made a plastic pocket for the DNI (the most important document that ever existed) so that both can be eyeballed by the police/prefectura/gendarmeria in a split second. I've also used highlighter on the pertinent parts of the document just to make it even quicker.
There are of course some 'jobsworths' about and once or twice a jobsworth has looked around my bike as if I'm a Mexican cartel member, but those are far and few between.
Yesterday I went to a deserted Shell station to fill up and was asked by a jobsworth if I had a reflective vest, which I don't, so he wouldn't serve me petrol. Remember, he had zero other customers.
Twat of the first order.
I then went to an Axion where they have the same effing rule, but the bloke gave me a wink and filled up the tank.
There will always be grey areas, but jobsworths can never see them.