I worked with a police helicopter unit once. The Chief Pilot had specifies that all crew wear flying overall with hi viz strips on the arms and legs. He told me that whenever another unit came in to act as cover he could tell something about the 'culture' by their manner of dress. As soon as the blades stopped turning out came the leather flying jackets and baseball caps. People reckoned that they looked like 'firemen'. But he reckoned that it was better that his crews were visible than that they were fashionable.
The manner of enforcement on hi viz may leave a lot to be desired but an individual's response to having to wear hi viz jackets is an indicator of their attitude to the concept of safety.