I have found that if they are a new member, they really don't know what a BOS is, or that it's a useless piece of paper.
If they are seasoned member, they are just paranoid or ignorant.
They are coerced into marking "YES" because that's the only option, there is not a "NO" box.
It's kinda the same way with shipping, the only answer is "NO".
As soon as I see BOS YES I close it and move on.
I wish there was a way filter out the BOS required ads, or just have a separate category for the paranoid.
There is a way, it is called Gun Broker, and where these folks should list their gunz