From what I've found so far, this is how we handle this type of situation:
- If there is a duplicate here for it, mark it as a duplicate (with a flag, or a close vote if you have that much reputation)
- If there is not a duplicate for it, just answer the user's question. Just because they failed to search doesn't mean it's not a good thing to add the information you do know/find to help them out. (It may help someone else in the future!)
- If neither of these apply, then the question probably has no answer, at all. :P
Whether the user did research or not, that's less up to us and moreso a case of the user having their own failings. We see a lot of questions posted here that would have been solved by a quick google search, and usually they're duplicates of other posts here on Ask Ubuntu, since they're so commonly asked.
It's not up to us, however, to adhere to the policy with 100% rigidity, so if users ask questions, just answer it (even if they could have solved with a simple google themseves), provided there's not a dupe of it already on the site (and there probably is, if it's that simple to solve)
Downvotes are a different story, and we discuss that elsewhere...
Basically, downvoting is your choice - you can either downvote such questions, or you don't down vote. It's really your choice , and there's no real policy for or against downvoting such questions. Just, don't abuse it.