Actually I'd be more like an eight year old (playing some linear console game on my Nintendo 64) if I ran into an invisible wall and didn't care

Technically the invisible walls are easy to remove, I've seen them in the GECK around many of the exterior mountain cells.

I believe they exist to prevent the player from entering certain areas except via the path they choose - which I think stems back to Obsidian's days as developing mostly maze-line games where Bethesda makes open-world games. I have found this to be the case in the game in many places, where in Fallout3 the areas were always designed so that the terrain defeated you if they didn't want you going into a certain area, where as in New Vegas it is clear I can make it over certain hills but am artificially blocked. Its not a complaint, just a difference in level design style that I found notable between the two games.

To me this makes sense in the respect that Obsidian prides itself on the strength of its writing and questing, where Bethesda is famous for its world building, engines, etc. It is thus no surprise that Obsidian would care more about forcing the player down certain paths so that the scene fits the story better, where Bethesda would be more interested in making a homogenous world that fit together perfectly and makes sense on the ground. I find the styles are complimentary to how their worlds are built, and if the artificial walls come down that will allow the player to break the story line in places that the devs didn't want us to.

Its a difference you can either get used to or wait for a modder to delete the invisible collision barriers in the game and bring down those walls - but as mentioned several times, there will be unpredictable and likely quest-breaking if not story-breaking and certainly immersion-breaking consequences will result.

Miax

There seem to be three types of invisible walls.

1) West, these are probably going to disappear when DLC is removed.

2) Around significant sites (ie The Fort and Hover Dam). These are because of sensitive story context.

3) At the top of hills and mountains, especially seen along the east near the Colorado River.

The ones that cause me the most trouble are the #3 category. These are all over the place, and serve little purpose, other than prevent you from going to a place that your follower or NPCs can't. This was a non issue in Fallout 3. Instead, if I need to go somewhere (Cottonwood), and I'm traveling from Novac, I have to find the path for no other reason than invisible walls. They get in the way of basic traveling around the waste. The point of this game is free roaming and exploring. Otherwise, you can't call this game free roaming because you can't even travel through non story line story.

I can understand #2, but 3 is annoying, and 1 seems a lil dumb its like they wanted the map to look big but i don't know. I do love how they put lots of places in the game though.