I worked for years in a big city ER. We would routinely...frequently...get city's cops in for the smallest stuff. Minor cuts and bruises...the kinds of things that wouldn't even make a 5 year old cry. And they were always looking for 3 days off. And the unwritten rule from the department's medical director was to give them a letter because we depended on them for protection when a person would come in threatening us with a weapon.
OTOH,however,we very,very seldom saw the city's firemen come in. And when they did you *knew* that they were sick/injured. They were *not* fakers!