If you played Fallout and Fallout 2, you could pretty much walk through them without so much as even hearing about them, let alone encountering them, however, if you encountered the Brotherhood of Steel and decided to be their gimp and do some obnoxious task they apparently cant do what one man can apparently can, they give you a suit of their armor and access to their tech.
Now, my question is, with this style of system of 'you may never even see them' in New Vegas, can we be expected to do some other gloriously difficult task for good tech from them?
(I'm only omitting F3 from this post since Eastern BoS are required visits)