From your link:

"A common trope amongst police officers in the United States is the aphorism: "If you lie, you die." This is indicative of the essential need for trustworthiness in the job—police officers are society's observers, enforcers and professional witnesses—and a warning that any deliberate falsehood can undermine the officer's continued usefulness, resulting in termination. Such terminations have been judicially enforced.[20]"

I personally know of 3 cops who lost their job for dishonesty. It's not even stuff like planting drugs, but turning in fake tickets (court copies never submitted, just office copies).

Further, look up the Brady List. In everywhere I've worked, if you're on it, the Commonwealth's Attorney will not take your cases. Period. If your lawyer loses a case where the witness is a cop who has lied intentionally on record, you have a crappy lawyer or a terribly corrupt judge AND jury

I practiced in Virginia for about 6 years. I handled approx 150 DUIs there. It is in the officers best interest to exaggerate their findings while investigating a crime. So ok. Yeah. Most officers don’t “lie.” But they certainly don’t act objectively either.

You know the onerous discovery policies in Virginia. Prosecutors don’t have to give you much. Even the Constitutionally mandated stuff is impossible to check because the only people who could, defense attorneys, have no way of knowing what exists.

Last, and I think this was op’s point: a lie only becomes a lie if it can be exposed as a lie. Most statements are very difficult to outright prove as a lie. This goes for defendants claiming they have someone else’s pants and for officers who are VERY sure she had bloodshot eyes “which in (their) training and experience are consistent with intoxication by marijuana.”

As a note, the thought process behind the ‘if you lie you die’ theory is contingent upon one thing. The cop has be caught lying. This is primarily because the cop has now made it practically impossible to testify in court on any charge he may have investigated.

The early history of the LAPD (1860's to 1920's) is basically a history of systemic corruption, complete with many many accounts of perjury. I highly recommend The Dollop podcasts on the subject.