Posting on a hacking forum isn't going to necessarily get you banned unless you, of course, say you are hacking or make the assumption that you are. He could be a legit player who would come this forum knowing many eager hackers are ready to sell their hacked items to him.
There's a 50/50 that he could be a hacker trying to buy items or a legit person buying hacked items but i suspect it's the latter...