I've made a career writing about fictitious anti-heroes. To create these worlds, I've spent a lot of time with active members on both sides of the law. And if I had to pick the most interesting of the two, the choice is obvious - we all love the guys in black.
Never in the history of 'The Shield' was the word 'LAPD' ever mentioned. We would mention districts, like Wilshire and Hollenbeck and Marina, but Farmington was a fictitious district, and we never actually uttered the word 'LAPD.' So that was sort of the deal we made with them.