I totaly agree with your idea to clean up a little the forums, however restricting to only pilots you will loose a lot of enthusiasts like me that only here have a voice in the aviation cyberspace. My idea : If you visit Cathay Pacific virtual pilots web you will find that they have smartely selected the forum users by using a technical (serious) questionaire. Other places ask you a tecnical question i.e. Airbus:wich color hydraulyc system is powered by RAT. Boeing: RR powered 747-400 how many are the autostart push bottons? etcetera.