Yeah no kidding.
Basically, BYOAC isn't craig's list, it is a hobby site, and the reason why you need some posts to go into a thread like B/S/T is to establish that you are not a spammer and are a member of the arcade community in general (Be it for hobby, nostalgia, etc). Also, long time members (such as Ginsu) have a much less likely chance of ripping people off, as they are a member of the "family", so familiarity may be known to breed contempt, it also breeds a better environment for selling or trading.