I don't remember the DLC for Fallout 3 Requiring a network connection to use, so why does the New Vegas DLC? I took my system down on a trip to a friends house who does not have an internet connection, and was unable to access the addons I had purchased. If I have to be connected to use them, that is not purchasing, that is leasing. What is the reasoning behind this? Is there a way to store them on my hard drive?

Steam or D2D version?

Steam works fine in offline mode (just checked) as I cannot speak for D2D.

Steam works fine in Offline mode. I have tried it before. It works at least with Dead Money, no clue about HH.