Convincing them to leave by choosing these dialogue options (no skill checks required):"Are you deserters?"; "I guess I can understand that."; "Why not just turn yourselves in?"; "I imagine the NCR doesn't deal with deserters kindly."; "It would be safer to run and find someplace to hide."
After restoring order to the town of Primm, the Courier must travel to a different location and pass three days without visiting Primm. Once this is done, visit Primm's Vikki and Vance Casino. Upon entering, the Courier will be approached by Layla and her band of thugs, who heard Primm is ripe for the picking. A conversation with Layla will reveal that they are NCR deserters driven off by the news of the Legion's increasing presence on the other side of the river, and had turned to raiding after losing all their money gambling.
There are three possible ways to handle the group:
Convince them that there is law back in Primm with a Speech skill of 30.
Pay them off with 100 caps (they will accept 50 caps if the Courier does not have 100).
After they are gone, the Vikki and Vance Casino will open up again and will resume functioning as a normal casino.
During conversation, Layla mentions that she and the other deserters will head to New Canaan.
Ending the quest nonviolently will cause loot in the casino (except for the cash registers) to become unowned. Looting them will no longer be considered theft.
↑Courier: "Your turf? I guess the news hasn't reached you yet, Primm has law again." Layla: "Fuck, we lose again. We heard Primm was ripe for the picking, so figured we could come here and shakedown some of the suckers. We weren't expecting a sheriff here." (Layla's dialogue)
↑Courier: "Are you deserters?" Layla: "I like to think that we are Prisoners Of War that managed to escape before capture. I don't know how long it'll be before the Legion crosses the river, but sure as fuck I don't want to be wearing a NCR uniform when they get here." (Layla's dialogue)
↑ 4.04.1Courier: "So that's it? You've resorted to robbing and raiding to solve your problems?" Layla: "Our luck has gone south since we lost all of our money gambling in Vegas. We didn't go AWOL from duty to become raiders. But we've seen what the Legion does to people that survive their battles. We wanted to be gone before the fighting starts. And we heard there may be some safety up in New Canaan." (Layla's dialogue)