Dick,
I'm all for seeing the buyer get the best price also but it's the seller's thread and he can put whatever price he wants on his item. At that point, it's up to the buyer to determine if that price meets his budget and/or how badly he wants the item at that price. A savvy buyer will usually do some comparative pricing on his own.
If a prospective buyer came to me and asked if that was a good price, I'd have to be honest with him and tell him that I could get him a better deal.
If I'm not asked, then it's none of my business.
I know that we, as a community, want to look out for one another and give a heads-up when warranted. I think that is truly noble.
But now, let me offer this. Did anyone think to look-out for the seller?
95% of the CMs, CTecs, etc. on this site know that these calipers can be had for $15 all day long. The vast majority of them also knew that this thread would end-up like this. Did anyone posting in this thread ask if he (the seller) could 'move' a little on his price?
One more crumb to be considered food for thought.
Maybe there's a reason the seller was asking that particular price for his item.
I know that most of us do what we do on this site because we care; that's a good thing. Those that care, have my respect.
The circumstances and very nature of this thread is a 'sticky wicket' to be sure. There is no black & white. It's all gray area.
Maybe, if we can now borrow the OP's thread for a continuation of the discussion, we can sort out the details and arrive at a better understanding of what's proper and accepted etiquette, because after all, don't we all want to strive to be better at the way in which we conduct our business?