You do realize how much of a huge exaggeration that is, right?
No, because that's how the rule was conveyed to me, ad verbatim, by two of the admins on the server. "No matter what, you can't kill people in this game if they submit to you. They have to agree to let you kill them."
Like I said, I visited several months ago so it might have changed in the meantime, but that was the rule when I played.
No character could ever last that long if they were to do all of those things, no matter how much they submit. If a criminal keeps deliberately loving with a particular ruler and his people on multiple occasions (robbery and murder, especially of close friends, for example), then the ruler is pretty much free to do whatever they want to said criminal.
See that makes logical sense, and I brought that up to the admins. But they told me that no matter what a character does, they're immune to death if they submit before being killed.