I am thinking about attaching a fondant ribbon around the top sides of a buttercream covered cake and was wondering if this would work. I've done it before with fondant covered cakes, but I am not sure if the weight of the ribbon around the top would just pull the whole thing down Is there a way to do this and make it look sharp? Thanks for your help!

yep, it works. just make sure the bc is well crusted. roll the ribbon up jelly roll style, and unroll it as you go aorund the cake. use water for glue

HTH!