Yes, but you see what I mean? The CSS class definitions in the forum files are hard coded, and may not gel with the user's present stylesheet, so would have to be changed (no way around that one).
As they are style definitions if they were in a separate file (like languages or templates) they wouldn't have to be changed/hacked each time an update was released
For example for some IB2 skin installs, the borderwrap/tableborder classes are interchanged.