Well, I gave the round table a shot but the mod was just a complete tool.
I find it hard to believe PD hasn't read any of the books, but its possible. I was thinking "plausible deniability" with all the nays on who read. I'm sure it's in their contracts not to divulge (under penalty of death) any of the show's plot lines beyond not only the scope of the current episode, but beyond scope of ADWD especially- too hard in today's communication system to prevent leaks, so actors prolly don't know squat.
But still a good strategy to discourage info seekers...hey, man, it's just a gig. I ain't even read the books. Latte?
Would be smarter to let RW go as written, only she's left for dead and found by BWB and revived. The emotional stress and / or brain trauma has left her mute and vengeful, and kept as more of a mascot by BWB than a leader...and the BWB do nothing to discourage the "UnCat" rumor, it's much too valuable in terms of propaganda.
Plus, if Lady Stoneheart doesn't end up w BWB, a lot of "The Old Gods..." Episode...well, the vow is the important thing to Brienne's development so may not be a big deal.