Making DNF SE friendly probably has it's negatives, but I would think the positives would definitely outweigh the negative by a long shot.
Think of the internet as a group of islands. The more you are connected with the other islands the better chance you will be able to sell your goods
Here is what happens when you sell only to a few people:
http://www.whyy.org/tv12/franklinfacts/apr0402_4.jpg
As far as "end users" finding your name on Google for dirt cheap, I think that is nobody's fault but your own. Think about it? Whose fault is it? If you put up "good" names for sale at wholesale prices then you had better be willing to sell them at that price.
I think it would be a very grave mistake if DNF closes it's Sale Forum to spiders. That is like sticking your head in sand.
Instead of embracing technology most of you are running scared. I've got news for you. Either adapt to the new ways of doing business, or close up shop now. Do you realize that "search" is how people actually find things nowadays? Or am I missing something?
Try this. Instead of peddling domains. Get serious about your business, and make your sales thread, spider ready.... (hmmmm... Let that cook your noodle)
That's my .02 for today! Hopefully it woke some of you up...