No, this isn't a reference to @hillbillyToad.
During all the hullabaloo the other day and me fretting that I might have irrevocably destroyed the metadata, Frank Davis showed me a cool little trick.
In the Admin tool go the BMM layer, right click on the model you want and select "Duplicate with Presentation Catalog."
You'll then be prompted to name your new BMM and Presentation layer.
Enter in the new names
And you now have a copy of your BMM and Presentation layer
What good is this you ask?
Well, it will allow you to do metadata development without affecting what any report writers are doing. It will also allow you to blow things up, quite easily if you wish, without major repercussions. That's nice to have.