I was wondering, when you got to boulder city did you kill Jessup and all the Kahns or let them live? For some reason i took pity on them and let them walk. I figured between his friend dead on the mattress behind him and Benny scamming them, he had seen enough already. Especially if you read the graphic novel that came with the CE.

I killed them, didn't know you can talk to them!

Hey, they didn't pull the trigger and frankly, hadn't they done the job, someone else would.

That said, I've mostly opposed the NCR as a whole (helping only individuals with their own goals), and I've tried to spare anyone capable of wrecking chaos and havoc in the wasteland, or that could somehow benefit me.

I let them live because the Khans never seemed very evil to me. They were just doing what they had to to get by. Doing some of the quests for them/involving them later on made me empathize with them a lot more. They're probably one of my favorite factions, its just a shame they had such a minimal role.