I disagree, slightly.
We should look to past MTA servers for character kill guidelines. Nearly every community I have been a part of on that platform has done exceptional work making it fair.
CKs, unless just accepted by the person on the spot, should be applied for and approved by high ranked admins who assess the killer's reason, their plan, their method of execution, and most importantly their evidence. If they meet the criteria, they earn the right to CK their target.
It's a good way to make it fair (ie you won't be killed for no reason), it stops people from trolling gangs and shit (ie running through the hood doing /s fuck niggers), and it promotes fear roleplay (you never know if the person has the ability to CK you or not, so you lose these instances of people in a robbery saying "just kill me then"). Then, if you have an issue still, you can appeal against the CK. But given that high ranked admins are the ones judging the evidence to begin with, 9/10 you deserved it.
Just my two cents here.