Under the trivia section, stating that attacking/murdering him results in no Bounty, I would like to argue that it may just be a bug.
I attacked him (sadly didn't kill him in one shot) and received a 40 Bounty for assault, then increasing by 1000 for murder. Yes, this was at the inn / hearth (where ever it was). I even got him as he was getting up from his seat, which is located in a room, isolated from other guests. So it's really either you kill him in public and receive nothing or kill him secretly and get done for crimes as you usually would.
It isn't saying that you recive no bounty for killing him, it's saying that, as opposed to normally when an npc comes across a body they usually neal down and make a comment such as "I'm going to find whoever did this" or such things, the patrions of the inn don't do this and completly ignore that fact that Lurbuk is dead, like they don't care.