I could see it going both ways. If someone is interested in getting more information about a poster and that's more important than keeping it secret for bidding purposes, then I get posting it and boning-up on the info. But, if someone outs the poster just to make sure the price is driven up so as to protect that person's own high-price investment, that's nasty. But, practically speaking, I agree with Rich that there is no etiquette, and personally it doesn't put my nose out of whack.
I'll tell you, though, I have seen postings like this and I have gone out and won the poster from the person who posted it, so beware fuckers.... I'm out to get ya!