I am going to disagree with this suggestion, although, I do agree with the fact that a big percentage of players do not roleplay fear properly and that when you get PKed you lose little to nothing. So I think the best option for the time being would be to be harsher on the consequences of a PK.
In a perfect world, this suggestion would totally work, but sadly it won't work with the current mindset of society in general, not even the playerbase or the server.
I would like to compare it even with money. I think it is safe to say that, on a perfect scenario, pushed towards realism. You could even set the prices of everything to 0 and people would be able to afford everything they want, as long as it worked for their character stories. Would this work? Of course not. And I don't even need to tell you why, as you read this, you can think about the multiple ways and scenarios that this would be abused.
If we were to have CKs all the time, instead of having the PK/CK as it is, we would face multiple unfair situations that have been written here by some of you. No, I wouldn't be happy if someone that played 100 hours on a character could just dictate when the character that I have played for over 1500 hours can die, most of the times possibly for a very poor reason.
Yes, in real life you're not protected, but as sad as this sounds, we can only compare the game to real life to a certain extent, due to the mindset and limitations of the game and other variables even, such as time.
If we made the game exactly as real life is, we wouldn't be able to age up characters, prison times would need to be roleplayed as OOC time, the economy would have to be completely revamped, gun stores wouldn't have a limit of guns you can buy, people would need to stay over 1 week at the hospital when they get injured (even if that meant NPCing and roleplaying by themselves), there would need to be a business for every sort of need your character has (insurances, supermarket, pharmacy etc) and this list could go on and on and on.
The point I am trying to make here is, as good as this sounds in theory, this wouldn't work out. The game is still a game, there will always be limitations to what extent realism can go, it is sad, but that's the truth.
This is just my 2 cents anyways.
Thanks for reading.