I don't really like "last resort", because it sounds like we expect people to spend hours searching about and only post on SO if they are complete failures. That's not the idea; rather, we expect people to ask questions that are sufficiently well thought out that they can be asked that are specific, detailed, and interesting, that they add to the community in some fashion. Many of the questions that are asked here have been solved somewhere before, and are findable on Google; that's not a problem, and there is significant value in having those questions also answered on StackOverflow/SE sites.
What we don't want are questions that are so trivial to be answered by simple reference manuals, because SO is not intended to be a site for the primary purpose of learning the basic implementation of a language (although you can learn a language from SO, as has been discussed elsewhere, you should be learning the basics first elsewhere). This ends up being a bit different on a tag by tag basis unfortunately, because in "busy" tags (say c++) there are sufficient difficult/interesting questions that you would simply never get an answer to a simple question. On sparse tags, however, like sas, where you get a few questions a day, you likely would get an answer simply because there aren't any other questions to answer.
While I don't like the term "last resort", it is probably best to also remember that one is asking for several people to take some time out of their day to answer the question. Just like I wouldn't ask a colleague how to do something that is trivially answerable by looking in the SQL manual, SO shouldn't be the first place you look, unless you know it's not that easy. I just don't think that "last resort" is exactly the right way to put it, either.