She is the leader of a group of 3 thug deserters from the New California Republic trying to escape NCR territory in order to avoid fighting Caesar's Legion. They have turned to raiding after losing all of their caps gambling. She says she and her group are trying to get to New Canaan.
Killing her, or her team of thugs, as they flee after resolving peacefully has no gain or loss of Karma and items in the casino that have changed from owned to unowned will remain lootable without loss of Karma. Their bodies also remain in the casino.
"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 an NCR uniform when they get here."
ps3pc When killed, the bodies of her and her thugs will not disappear from the game. [verified]
Oddly enough, their bodies can be used as safe, movable storage.
ps3xbox360 If asked if her group are deserters, Layla will say that she doesn't want to be wearing an NCR uniform by the time that the Legion arrives, but the subtitles say "NCR inform". [verified]
pcps3 Layla's group enters the town from the north, and may take the narrow walkway above the eastern side of the underpass. Rather than becoming stuck on the destroyed cars in their path, group members will continue their running animation while soaring up in the air to a height exceeding that of the wall surrounding Primm. [verified]
pc She will act as a normal NPC and wander around the Vikki and Vance Casino, even though the rest of her gang has been killed. [verification overdue]