It seems a common occurrence that new users to the site post their code without an extra indent, leading to stuff looking like this:
import os import sys
def foo(): print 'hi'
return os.listdir('.')
etc... people then usually implore the user to fix it in the comments, or someone will come along and fix it for them.
Feature request: infer whether code without an extra level of indent is possibly being posted. If so, when you click 'post your question', it will ask you explicitly: "Make sure that if you are posting code, it is properly indented." You have to click again to submit the question.
This might lead to false positives. To minimize annoyance, this will only apply to new users, or users with < a certain amount of rep. This is based on the assumption that only new users tend to do this.
The benefit is less poorly formatted questions, woohoo.