RTFM is reserved for those people who keep asking questions, over and over, when they could have just read the docs. I'm more than happy to help people, but will eventually stop answering their questions if they are in a wiki somewhere, and just point them there.
At some point, you have to help them help themselves. If politely pointing them at the documentation doesn't work, it's time to try shoving.
Oh, and in CS we often interpret RTFM as "Read the fine manual", which is significantly less rude. But also tongue in cheek.