This is an important thread and one which should enhance the value of the warung. I agree wholeheartedly with the idea of promoting ethical behaviour and as Alan Maisey has said using the utilitarian approach is probably the most functional in this circumstance. Promoting ethical behaviour is one thing, having all the members of the warung do so is another.
If I might offer a few thoughts .
In the code of conduct points #5
Do not engage in any commercially oriented behavior
Behave in a respectful manner towards other members, and their opinions
are particularly pertinent in this discussion. Point #5 is fairly obvious, point #7 is asking us not to treat our fellow warung members badly, that includes deceiving them as to the true purpose of our questions, and using their information for our own commercial gain without their express permission. I think it might be a good idea that all new members (and quite possibly all existing members) be asked to confirm that they have read and accept the code of conduct of the warung before being allowed to post. Secondly I think that a moratorium period between being accepted as a member and being allowed to post (2-4 weeks) might disuade opportunistic behaviour. Finally I believe any changes decided on as a result of this thread should be made to allow the warung to improve its role as an educational and sharing group and enhance the ability of the moderators to avoid exploitation of the group.