I'm playing a mainly stealth character, so I spend a ton of my time crouched and aware. I have a high Perception (8, plus Night Person which is a +2 to Perception and Intelligence at night), so I generally see enemies before they see me. On top of that, I have 100 Sneak and Silent Running, so I'm essentially invisible. Normally this works out well and good, occasionally I need to use a Stealth Boy to get a good shot, but usually the stealth can carry me through whatever happens.  
 
However, on going into Old World Blues, I've noticed that I always have [CAUTION] while in The Big Empty, yet I can still score Sneak Attack Crits on almost any enemy I see. While I'm inside of a building, I can go totally hidden, but when I'm in the overworld, it never goes down to hidden, just stays at Caution or goes up when I'm definitely spotted. 
 
This is a really big inconvenience, because I'm never sure if an enemy is looking for me or not and it's really got me on edge. Is anyone else experiencing this problem, or is it something to do with what my character is doing? It's not affecting my overall enjoyment of Old World Blues, I'm just wondering if it's a bug or if there actually is an enemy always looking for me for some reason. 
 
If anyone's wondering, I'm playing on the PS3 with no other DLC installed, and I've got the latest patch.

Asking if New Vegas has bugs is like asking if China has people. The game is just fucked. It's fun, but it's fucked.

I've had Old World Blues crash no less than three times in the few hours I've pumped into it so far, you just gotta go with it.

Yeah I had the same problem. Didn't bother me after a while though, because my character is so immensly overpowered that he'll just desimate anything that comes his way. I'm also playing on the PS3, but I have all the other DLC.

You're not alone, and from what I can tell from other forums, its just how this one DLC is. It seems to me that its something about robots that allows them to see my guy even with 100 Sneak + Silent Running (and sometimes even with a Steatlh Boy). I'm playing on the PC, so it's not a PS3-exclusive problem.