In Game Complicated Explination: The character in question recently consumed the heart of a black dragon. This has resulted in some hightened senses and will eventually lead to other changes in the characters physiollogy. The player later explained to me that he felt like it was appropriate for the PCs behavior to begin to change as well. I agreed.
Metagame Explination 1: This person,although having roleplayed for a long time, isn't the type to really creates things for his character to do. He goes along with the party, but adds almost nothing to the roleplaying aspect. Meanwhile the other two players have these complicated back stories, relatives, and love interests that give me plot hooks galor. I was thrilled that he went and did anything.
Metagame Explination 2: I have been trying, subtely, to encourage the PCs to explore their new home city, but the others have been involved in their own little subplots that I haven't gotten lots of results, or unsatisfactory ones. So, while he didn't really do what I expected, as they never do, I wanted to encourage texploration in the future.
Its interesting that most people have taken my question as somehow critical of the act itself; I wasn't asking how to deal with the character or the player, all I was asking was a straight forward XP for CR question.
Respectfully, I don't see why you wouldn't reward players for creating their own challanges, given that they also suffer the consequences of those challanges. They should be able to create the kind of situations they want to play. If you go around picking fights to get a rep or whatever one day you will pick a fight with some one bigger and nastier than you. Or someone with connections (as may happen in this case.) How is going into a bar and startign a fight different than looking for the nearest dungeon and starting a fight there?
In fact the other players have created their own challanges, things I thought either a bad or dangerous idea, but I let them go through with it and bear the rewards and benifits. One character went alone to see her half-brother, a powerful agent of a rogue city state ruled by the PCs enemies. Her own idea, not my instigation. I even suggested that he might try to send her home "for her own good" out of game. She went, he tried. She survied a fight with his numerous but low level household guard (another reason for my original question) and got away with the aid of a main NPC and another PC. Another character started studying some spell books he found in a cultists' lair, almost died from the backlash of a dangerously evil and poorly knownspell, has become invovled with a guild of occultists, and has recently taken on a tattoo that identifies him as a member of such. Even though he knows the Inqusition is looking for unsanctioned magic users, and he and his allies might actually need the support of the Church at some point in the future.
IOW, I am fine with the PCs doing stuff like that, knowing that it would have consequences. When the time comes I can easily get them back to my metaplot. In fact everything they have done lately, although not what I had planned, will serve all the better when the time comes.
And BTW the bar was the hangout of a Teamsters-like guild, so there will be in game reprocussions. And considering that this particular nation is run by the merchants and the guilds, that can be saying something.