So I just did this for my site mostly as a joke , but it works well and it is effective (thus far)
It doesn’t automatically catch the offenders, but when I (or any of the leaders) see it we set a tag on the post of “formatcode”
Then this happens the next time that user logs in
It sticks around until they correct the problem and remove the tag, so far we’ve throw it at a few people and the code ALWAYS gets cleaned up. It only shows up for the author of the post.
Anyways I thought it was fun, I haven’t made a plugin out of it (I don’t have the time) but its fairly straight forward javascript. If someone wants it let me know and I’ll post it