The idea jumped at me after reviewing two close votes in a row (granted, from the same user) that were homework assignments without any code in it.

Since a question that has no code in it, is 100% garanteed to be off-topic here, can there be a "code-block detection" mechanism that prevents a user from posting a question that wouldn't have a code block?

Perhaps even pop a message saying something like this:

Questions on CodeReview.StackExchange must contain code for others to review! Moreover, the code must be working code for the question to be on-topic. No code? Sorry, no one can help you here!