Fallout: New Vegas Scripted Encounters

Within Fallout: New Vegas there are random encounters similar in style to those in Fallout 3. These encounters can happen at specific points or be completely random happening when they happen.

Fallout New Vegas Random Encounters
Several of the Random encounters can be replaced by the Wild Wasteland perk. Most notable of these encounters being the three alien surveyors past the ranch near a hovering alien ship, or the three old ladies in Primm with shotguns.

Powder Ganger Event
Potential to be encountered anywhere, as long as you have bad reputation with the Powder Gangers. A random Powder Ganger will appear and initiate a conversation then attack you.

Sunset Sarsaparilla Star Bottle Cap
This event is triggered after collecting several sunset star bottle caps. It is unknown if this can only be done in Goodsprings or if it occurs randomly after obtaining a set amount of caps. After collecting several caps in Goodsprings and possibly the trigger cap being in the Devil's gorge. The Devil's Gorge being East of the Goodsprings map icon on the pipboy.

After obtaining four (4) of the special caps a roaming trader named Malcolm Holmes will appear and converse with the player about the caps. The player can learn more information from Holmes or leave him be. If the player chooses to attack Malcolm Holmes he will retaliate, but will die quite easily. Looting the body the player will find several items including five to seven Sunset Star Bottle Caps (found 6 on him). The Sunset Star Caps can be pickpocketted off of him (best done with a stealth boy).

NCR Rangers
While traveling the Mojave Wasteland with a negative rep with the NCR, 2-3 NCR Rangers will appear, telling you to change your reputation with them from bad to good within three days, or else they'll attack you "without the pleasant conversation". If you don't listen to him/her, they'll come back and shoot on sight. Most of the time there'll be an Anti-materiel rifle on them and the NCR Ranger combat armor.