I would support that most definitely. People don't always post threads for a simply, clear cut answer, sometimes they actually want personal experiences (something no wiki post can/will give), or they want an actual discussion on the subject. Either way, using the wiki doesn't really contribute anything.
I understand if someone asks such as what combat level is a moss giant, or where are they located, but even a thread that asks the best place to train range from 70-95 is a legit discussion thread. People aren't just asking for places, so much as they're asking what and why people think their spots are the best, it's a competitive discussion (if you want to call it that), and it's another thing the wiki can't offer.
In the end, if you aren't going to contribute by posting an answer, then don't post. I really hate it when people post, Google it, or Wiki it, it's extremely annoying. Even if you think it's a stupid or common question, to someone else it might be a valuable bit of knowledge to know. If it's so easily found, why not just copy and paste the answer instead of simply linking them to a page where it "might" be found?