Maybe it could be hidden from brand new members, something like what you did with the ROTM Committee thread (just not permanently hidden). Then when someone has been a member for 2 months or if they have a certain number of posts, it would then be visible for them to access it. I like to think the integrity of 6GA as a whole would enable this concept to work. Depending on what the limitations are as to how this site is set up, this could be a deterrent for people to abuse the thread/section.
In addition, I am thinking perhaps some guidelines could be set in the OP (or a sticky if it's a subforum) that would clearly outline the purpose. Kind of like the large bold text in every OP of the Product Review threads, and even a few examples could be given to give people a clear idea as to whether or not their circumstances warrant posting. And if you saw fit, there could be a statement informing people that in order for this to serve its purpose the rules must be followed, and there are consequences if they aren't. Not sure if that's viable to you, lol.
Really though, I like to think none of that is necessary and the integrity that is typically found in the members of 6GA would enable this to work and serve a great purpose. But I know that's easier said than done.