If we serve the header:
X-UA-Compatible with the value: IE=edge
We can eliminate the "compatibility mode" / "make website ugly" button in IE9.
Before:

After:

This will add 20 or so bytes to every request we serve to compensate for IEs "unique" behavior and protect users from clicking this button by mistake.
However, in the history of meta this has never been asked for so odds are this issue is totally "imagineered".
Should we bother serving this header?