I just got jumped by legionary assassins outside Wolfhorn Ranch, at level 7. I've had encounters with them before in other playthroughs, just not at this low level because I usually don't piss them off till much later. I was roleplaying a hardcoe NCR trooper, so I killed Vulpes and the rest at Nipton (never done that before).

I had only a varmint rifle and service rifle with me, and low ammo from the firefight with Vuples and co. Luckily I had the one stealth boy I picked up from Joe Cobb so I hightailed it out of there with just enough HP left, shamefully leaving the merchant convoy I had been travelling with to be massacred by the assassins.

It's the first time in a while the game has surprised me, and it's pretty awesome.

I've never killed Vulpes on the first encounter, but if I did I'd definitely be waiting for the other shoe to drop.

I always kill em in that first encounter.
Why?
First off, I hate that dike head.
Killing the whole group will end up giving you some fairly decent weapons/ good loot to sell when you hit Novac.

Vulpes dies on all my runs... and I really like the guy. Just a shame for him I like his hat also.

My most recent run, Vulpes died in Nipton. I wanted to test out the Mercenary's Grenade Rifle. 3 shots to take out the entire legion contingent there.

Then the assassins showed up later on, while I was getting reading to use the rifle again, so I blew them up too. I want to rename it 'Visigoth'.

I killed Vulpes by Accident headed to nipton i forgotten to put off my NCR trooper uniform well he attacked and i was like whatever die then stupid legion , but i didnt got attacked recently by those assasins ,

I usually kill everyone BUT Vulpes in that Legion party, but I use a silenced Varmint rifle, so no Legion infamy. I've started leaving the dogs alive lately, however, because for some reason they respawn in Nipton if killed there.

They seem to respawn everywhere took over Nelson and still see dogs poppin up.