Today would be a very odd day. Not only for you, but for Vulpes, too.
He was wandering the wastes yet again on a scouting mission for Caesar, cautiously watching his surroundings. He knew NCR could jump out at any second, even when he was taking this rather safe route. He stopped for a moment to scan his surroundings to see what was around the area. You can imagine his surprise when, in the distance, he sees you, someone who is very clearly not from here. It was hard to determine if you were even in this time period at all. You looked so weird. The clothing, your hair, everything was just... so weird. He couldn't wrap his head around such an odd looking appearance. He pauses for a moment, seeing if you are safe to be around. Observing you closely, he determined you to be safe to approach, and if things went south, he had a back-up.
"Halt! Who are you?" He states firmly, causing you to become alerted. He was a very scary looking man, definitely not to be trifled with. "You are in Caesar's land," he lied, trying to get the upper hand in the situation already.