Yo. I saw some quick comments wanting examples and basis so; I have been within Judiciary aka the courts for 12 months, Sheriff's for 8 months and then Police for 18 months before Sheriff's. I have had 5 characters between Sheriff's and Police and 1 character within Judiciary throughout this time.
I have never been PK'd or put into death-mode during that time on any of those characters during law enforcement role-play, I have had alternative characters within illegal factions and/or positions. This has only helped me understand better the state of illegal role-play and how to better contribute to the experience of this illegal role-players while on my law enforcement character.
Personally, my opinion on the whole shebang is not a popular one. I believe that if you are PK'd on-duty, and it isn't a situation in breach of the rules, you should CK. Why? You have a radio in which you can call the entire faction over, some have a rifle accessible to them at a moments notice, you have armor on your character's body. If you died, it's tough shit and you should take the L and learn from it. Retreat, role-play fear, get colleagues over. Is your character seriously going to push against a gang when they are out-numbered? Do they care more about a license suspension than their own life? "This isn't worth it, lets get the fuck out." is something that should be said more.
Now when it comes to the demotion part, I honestly do not think demotions are the way forwards. Perhaps resetting their 'progression', they start from the time requirements for the next rank again, something along those lines. There has to be a median between fair and fun. I have written manuals in both Sheriff's and Police which are still used, I'd probably jump out my window after spending hours on that only to be wiped out by a metal mall-rat bat and demoted.
tl;dr imo there is an issue, there needs to be more consequences for law-enforcement and they should be held to a much higher standard than they are currently. However, these consequences should be set in place for everyone, illegal and legal. OOC bias will always exist, that needs to be mediated as well. I've got no idea on how though.