By far the most common edit that I have to make in SO is to correct newbie users who don't know how to format their code. This got me thinking: is there a way to automatically recognize when a post contains unindented code and present the asker with a popup or warning message? Simply pointing out that their code isn't formatted and pointing to the format button would go a long ways towards cutting down the difficulty that new users have. A relatively simple Bayesian classifier could probably catch enough cases to be useful.
I welcome implementation discussion and counter-proposals in the answers.