Connelly does not recommend fiber suppliments, but getting fiber from foods.
He is also definitely not as "low carb" as most low carb plans (although I haven't really compared with South Beach...that's the one book I have yet to read).

However, following PP and tracking my fiber, I noticed it was quite low (easily under 10 g) compared to "recommendations" from WHOMEVER. When I focus on fiber, I can follow PP and get my fiber up to 15 to 20 g a day. I would suspect most low carbers (not just PP) don't come close.

Are they going to DIE from it? I doubt it.
Can they not lose weight from it? I doubt it.
Can it be beneficial for them to up their fiber intake (naturally)? I personally think YES because i think our ancestors ate much fiber in their diets (easier to get things off of bushes and trees than to take down another animal from the hunt). My own speculation. But I don't think it is right to cast fiber off just because we can maintain regularity.

I really wish the Eades had left the chapter in about fiber.