Take out policeman and use construction worker, firefighter, and accountant, and I'd think most would back up their peers and co workers vs the gen pop.
But regardless of the situation, good cops will do their job to uphold and abide by the law. I don't think the lines are that blurred.
Depends. In many jobs people are mandated reporters and if they suspect a coworker is harming a client, they are required by state law to report them or they can lose their license, get thrown in jail or be fined. So, it really depends on the occupation. Some jobs have VERY strict guidelines about reporting coworkers.
The issue is that many of those jobs you described do not involve direct contact with people on a daily basis. Furthermore, those jobs usually do not involve a person's life being put in danger on a daily basis (except fireman). You would hope that cops are held to a higher moral standard than a construction worker, given their oaths to serve and protect the population on a daily and continuous basis. Thus, it becomes even more stickier when one cop covers for another cop, considering the high need civilians place on cops to be honest and moral, even beyond a construction worker.
Yes, the thing is, how many good cops are out there that will actually speak out against their partners and corruption within the department? As I said, its very cult-like, so many cops would fear retaliation and ostracization by other cops, and thus will remain silent. Its actually similar to the street rule, "No snitching." Police departments need to do a better job of celebrating those good cops who bring down corruption within the department, instead of ostracizing them. Its really an organizational problem. And there have been quite a few instances of this.