Having a technical occupation I think I am pretty good at understanding how to conduct a productive search. However, more times than not I find that other people have a hard time understanding how seach works. I have actually watched as users have typed in their exact question just as they would ask verbally. Searching a database of information is a skill, teaching the skill is realistic, banning them from posting for a period of time will just make them go away.
The only way that I have seen that works, to some degree, is establishing a list of FAQ's. If they don't get read, others can always post with a link and direct them to the appropriate information, along with a post saying "I found this in the FAQ's". It's not a 100% solution but with time more users wil check the FAQ's first.
This site is an excellent source for information, I'd also like to see it continue.
Just my $.02