It's not a negative thing to have a domain indexed. The reason threads have a high number of views is not necessarily from members on the forum but from guests who have reached your thread through google etc.
I have had sales from gold members who joined because they were a guest and saw the name. If you're that worried about it...don't post your high quality names.
i've argued your point as well.
publicity is a good thing imo
i've also sold names to people who joined dnf after.
on occassion, you'll find the curious (end-user/web novice) who wants to know what you do and how you got involved with domains.
they have know idea of a "domain industry" as such,
and when given a preview, they are very interested.
these buyers typically don't question your justification for pricing, when you can refer them to a website that shows a portfolio and references of past sales.
they realize that you are a serious business person and respect the values you've placed on your domains....simply by reason of association.
how you paint the picture, can be just as interesting as the painting!