Reddit comment:

I know this was meant as a "haha funny" post but it seems some people that post in this sub actually think this could happen. GRRM is co-executive producer and is in the meetings when these changes are made. When the "show runners" make changes you don't like, he is one of the people doing it. 

Edit for the people that really seem to want to believe he doesn't work on his own show. 

"We are already at work on Season 6. I met with David Benioff and Dan Weiss and Bryan Cogman [Friday] night and we had a long talk about some of the stuff that will be included in Season 6, but we haven't started writing that one yet," George said. 

Read more at...

http://accesshollywood.com/george-r-r-martin-teases-kick-ass-sand-snakes-in-game-of-thrones-season-5_article_104318

200+ Reddit comments:

http://reddit.com/r/gameofthrones/comments/34vsez/s5e4spoilers_george_rr_martins_reaction_to_last/

More on Ser Barristan:

http://pandawhale.com/post/62795/ask-the-maester-s5e4-the-tale-of-brave-ser-barristan-and-obi-wan-kenobi-the-faith-militant-and-lyanna-stark-and-rhaegar-targaryen