Fun fact: The reason why sneaking by the Ghost people sucks so much is because their Perception stat is glitched, it's supposed to be 0, but due to an engine quirk, having a Perception of 0 makes their Perception 10 or some shit, so that's why it's hard. It also doesn't help that sneaking accounts for what time of day it is, so while it always seems like night time at the Sierra Madre and dark, you can look at the clock and still see when it's actually day or night, and sneaking during the day has a massive penalty on your Sneak. So yes the sneaking mechanic sucks lol, but I've played F:NV and Dead Money so much that the entire DLC is super easy since I know where to run to, but first time playing it is pretty brutal.