I'd just like to put in my .02 though I realize I haven't been around here for long at all and I only have about 20 transactions, all as a buyer.
I just simply think that, as others have said, if the sale does not concern you then just stay out of it. If you have absolutely no intent of even throwing an offer then definitely stay out of it.
The onus is on the buyer to do his/her homework, period. Isn't that how all business is handled or any negotiation? You start high in price and go from there. Reality is, even if you put a price up that was below avg eBay sales over the last few months and well below BV, you're still going to get people that will lowball the hell out of you (which is a pet peeve of mine - if prices are stated as firm then why are you treating it like OBO?).
The thread that was posted as an example - I hate to pick on him but after the offer was made which was $300 below asking price, and it was declined, it's over. Take it to PMs at that point. To me it's almost like "if I'm not going to get this card then no one will." I don't think that was the intent but it came off like that. And then because of these "accusations" you can not only kill a thread, but kill someone's ability to sell for awhile by doing that. You cast doubt like that and everyone starts to get trigger-shy. I think PM'ing someone that posted interest to the effect of "hey just looking out for you...that card normally sells for half of what they're asking" is great! But do it via PMs not publicly. I'm sorry about the length and I know since my post count is so low this probably doesn't hold much weight but I couldn't resist. I think if we started calling everyone out for asking for too much we need to look at the top down, literally. Admittedly, I still have absolutely no idea why Harper and Strasburg cards command so much $, and as an extension guys that have played 20 MLB games or none at all (Bundy, Profar, Manny, etc - they command so much money)! It's crazy that in this world, the "stars" don't seem to be as valuable than the potential stars. Every time i see these cards going for $500, $750, upwards of $1k its just mind-boggling to me. alright now I'm babbling.
P.S. Heresva good example (though admittedly I agree with almost everyone): $10 each Autograph Blowout Sale - Over 1,000 Cards - 1/1's Included