Carnut, that's actually a very good idea, if there is a way it can be implemented... although still there are ways round it.
I'm not sure if I can make any suggestions about how to solve this problem to be honest, it's clear the people who I would describe as the 'core members' (those of you who have been here the longest, post the most puzzles and posses the most knowledge!) of this 'site are not going to be cheating in this way, and hopefully once all the members have read this topic and seen the reaction to it they will do the honorable thing and self-moderate their behaviour.
I definitely think there should be added a new rule that makes it clear that this is NOT an acceptable way to play the game - There will be no way to police the policy, sure, but again hopefully everyone here is honest enough to play fairly.