Teach git-gui about merging around modified files?

"git merge" will happily merge a change with modified files in the tree as long as the merge doesn't touch any of them. However, it appears "git gui" won't even try if there are modified files at all.

How hard would it be to fix this, or is this an intentional choice? I realize that commiting even untouched files before a merge is safer, but I'm tasked with migrating some CVS users to Git, and I'd prefer to be able to introduce the new Git workflow slowly.

(I'm happy enough with disallowing merges that actually touch modified files, so I'm not looking for any kind of in-working-directory merge like some others were. I'd just like the "git merge" behavior to work in git-gui.)

-bcd