Nah, people don't get pissy. We do it all the time in the shoutbox. Before you say anything though, scour the feedback forum for their feedback. That doesn't necessarily mean you will have a 100% positive experience, but it's better than nothing.
Also, I agree with you. As I said before, I sent a message to a moderator to check this guy out. I don't know if anything was done or not, but it immediately threw up a red flag for me, when I had seen 100% of his posts were in the for sale section.