> Projects need contributions from everyone of all skills and levels of expertise.

I disagree. I find that politely rejecting or rewriting contributions from people with little experience or clue is a serious time drain for a maintainer (as well as a trial of patience). This goes even for documentation, which, when written by people without a clear view of the software, tends to be confused and misleading.

I try to handle such contributions gracefully anyway, with the idea that some of these people will use the feedback to grow into better programmers, but even that is unlikely to benefit the project -- the time span it takes to go from clueless to good is probably longer than the period in which the person is involved in my project.