I know you said Experience gold sellers / buyers responses only please. but Iv'e never heard of this RWT detected thing before and Iv'e been on rs for a while now. It's probably a spoofer from JaGex (if it is from them in the first place). I wouldn't worry too about getting banned much but if I were you I would probably dump my current stock.
Jagex could care less about RwT as long as they're the ones gaining the money for selling items and shit. But when it's not in their jurisdiction they won't have any of it.