Don't Poke at the Bear!

Don't Tread on the Bear! is a unmarked quest in Fallout: New Vegas.

Walkthrough
If the player has not allied with the NCR or done anything to decrease reputation with the NCR faction, the player may be randomly visited by three NCR Rangers. The Rangers give the player three days to begin an alliance or improve reputation with the NCR. If the player does not improve reputation after three days, the side quest Don't Tread on the Bear! will commence.