Wrapping Ribs and Butts can give you more control on the final product as you get closer to the end of your cook...
When my cook gets close to "done" I check the texture of the meat and determine what it needs...1 hour, 1/2 hour or let it ride...It goes along with idea of adjusting your cook time, temp and plan based on the many changing variables during the cook...
So to ask: Foil or Not? It depends on how the meat is cooking and the texture of it as it gets close to "done"...this needs to be assessed as you near the finish line...
...I think foil widens the "window of done-ness" with little downside...
Long story short...Foil..