There are more than health code violations. There are kashrus problems as well, along with choshen mishpat problems. Those, of course, is forgetting about the tzaar baalei chayim problems from leaving chicken crates piled on top of each other without food or water, causing chickens to suffer from both hunger, thirst, and being defectated on by chickens in the crate above them. Chicken crates are tossed around haphazardly, resulting in broken chicken limbs and rendering them treifos. Secondly, the speed of the shechita results in many treifos and neveilos. Finally, some of these places sell the same chickens over and over again.The Kav Hayashar brings a story with the Arizal of someone who was cursed with childlessnesss for causing chickens to suffer. Mr rav recommended using money unless the place is a certified place. Otherwise, “yatza scharo behefseido”- your loss is greater than your gain.
As for mesira, the din of Rav Moshe sternbuch stems from the gemara in bava Metzia (somewhere in the mis-pehs, forget where exactly) where Rabbi Elazar bar Shimon worked for the government arresting Jewish thieves. There is a psak that it’s muttar to work for the government as an auditor. Every case needs to be addressed to a rav, of course.
I think in Boro Park, the minhag is to call a private tower to tow the offending car blocking the driveway. Mesira isn’t omerta. It’s not about protecting criminals- it’s about preventing damage. It’s hypocritical for someone stealing Jewish people’s money to say “you can’t maser on me”. Both are hezek mammon. If the only way to stop him is mesira, it’s not an issur mesirah. As always, ask a knowledgeable rav first.