Trailers weren't allowed in season 1. In season two that changed and even then it was by a narrow margin.
Look man it doesn't get much more clear cut then this. If you want to talk about charqcters who aren't in the show yet and casting decisions made in the show for characters that aren't int eh show yet then make them in the thread where people read the book.
There's no point in posting it in the no spoilers thread anyways, people have no idea who the hell you're even talking about but now they know x character and x character will be around at some point as I as a non reader would rather not know that information at all.
You have a place to talk about it, go there and talk about it and leave the non spoilers thread alone. It's not rocket physics.
Also with your whole "the only reason it was enforced was because a mod was bored" no, it was reported. other than the politics thread the GoT thread is the single most reported thread on these forums. Because people want zero spoilers of any kind.
Get over it or don't, it's up to you really. Either way it's not allowed in the no spoilers thread.