FHP; trooper hats, duty uniform...
A few years back, a sworn deputy with a central Florida county told me how; "in the old days", Florida Highway Patrol Troopers were mandated to wear the issue hats when they made traffic stops.
After a few FHP state troopers were attacked or shot at while fixing the headgear, the agency changed the SOP.
I'd heard the NYPD & the PBA union(police labor group) had a dispute too over uniform caps.
While I served on active duty as a lower enlisted MP in the early 1990s, our company CO(commanding officer) got a huge bug up his backside about how we(patrol MPs) wore our issued duty gear. The same Captain(0-3) never said #%+* to the MPs under his command while he served as MP operations officer on the same post.