Well, I'm not a police detective, but as a private investigator, I seldom ever wear one while working. That's because generally, I'm trying to blend in, and let's face it: fedoras don't help you blend in.
When I first started PI work, I wore one even less often, because I didn't want to be confused as some kid who was merely a wannabe (I was nineteen when I started training as a PI). Only my supervisor/mentor and fellow investigators saw me wear a fedora to our meetings. By then, the knew I was serious about the work, and liked that I wore fedoras, as they fit my personality.
I'm currently working as a security officer at a university police department, and while I wear a fedora into work most mornings, a fedora isn't in the SOP's (standard operating procedures) for my uniform, so alas, the fedora goes in my locker, and a standard black baseball cap comes out. That is until I go home.
Thanks for posting that article by the way, JB!