Fairly often I see questions which are in fact about Tex & friends but are closed & marked off-topic. One reason I see listed in the comments is:

This question is off-topic because it simply stems from a misinterpretation of the [insert-pkg-name-here] documentation.

Isn't the appropriate action to answer the question with an explanation of how the user is mistaken? Explain what they misinterpreted rather than just designating their mistake as off-topic?

If one user has misinterpreted the documentation, other users have or will make the same mistake. An answer explaining the mistake is more useful than an 'off-topic' tag.