Yeah, we'll see how they tweak it, but I'm assuming the intention is to make it so casual PvPing will not turn you into a murderer. You will gain murder points every so often if you attack people who're near your level that haven't been engaged in PvP, but there's also a murderer point drain that happens over time and with gaining xp. I think their intention is to have that balance out for the casual PvPer.

Now if you wander around an area only fighting people who are not trying to PvP, all innocents, you might accrue some murder points. But it sounds like the fastest way to get points is each ganking the same person a billion times or killing people way lower level than you.

Also yes, I think they could easily add a player bounty system to this or a way to find people who have the murderer tag.

Keep in mind that anyone who's actively engaging in PvP will be a criminal. So if someone attacks you back, you're good to go. You'd have to purposely be killing people by surprise, then running away and finding someone else who hasn't been PvPing to kill them in order to gain a lot of murder points that way, and yeah, that should be discouraged.