I have noticed a pattern while browsing the Android tag on SO. I will not mention names but there is a guy going around posting a cookie cutter "get a stack trace" answer, with a picture of Eclipse's logcat. This is something that should really be a comment, not an answer. I left a comment to him, but, he seemed upset, so I retracted it. He cited that he thought the newbies needed an informative resource. I think to most people, it would be a bit obvious why this is not the right solution to the problem.
Each time he posts this, he replicates information he posted previously. It's a canned answer, and offers no value to people who will find these questions when they are searching from the Internet. Which should really be, the primary concern. If OP is too lazy, or doesn't know how to get a stack trace, a simple comment is what they need. Finding a stack trace is really not rocket surgery.
Now, the problem still exists that needs to be solved: how do we deal with the general case of users in specific tags always needing to be told the same thing, again and again? Well, it so happens that this problem has been around for a long time, and it has been solved already. The solution is an FAQ. On IRC, if you ask a dumb question in a programming channel, usually they have a bot. Someone in the channel will type a trigger that will cause the bot to shoot you a canned answer. Such as..
!stacktrace -- "x wants you to know, that you should provide a stack trace! Here are instructions http://www.stackoverflow.com/faq/39r99fsd9f"
So, this feature would be really cool. I think each tag on stack overflow should have it's own FAQ that users can contribute to. Then, if a question comes up, that isn't a duplicate, but in the process of answering this question, OP needs to be told something repetitive, we could leave a comment in his question, with the special syntax regarding the case he triggered. Such as @John!stacktrace -- to tell John to get a stacktrace. Or click a button, or whatever UX you can dream up. The idea is to eliminate the replication of answers without having to eliminate the question itself as frivolous, because although something fundamental was missed, the rest of the question may still have value. Sometimes people just need a little pointer. This feature would accomplish that.