The problem with the guidelines is that most people dont bother to read it. Like the pinned stuff about impedence and strings and all the other questions that get asked over and over again, nobody looks at that either, or even reads posts properly that they are replying too.
Can the guidelines bit be made bigger, much much bigger, so you cannot but see it.
Even better, when someone starts a new topic in for sale, instead of an empty page they get the guidelines and have to delete them before they can create their advert. I dont know if this is possible with the board technology mind.