I saw a couple of cakes recently that had strips of burlap wrapped around the base of the tiers. They were delicious buttercream, too. And I'm sure that they had some fabulous burlap fibers embedded in that icing.
Here's what burlap looks like:
Mmmm...check out those hairs on the surface of the fabric. Nice, that will be delicious with the icing.
If that isn't enough for you, yum yum, look at those rolls tossed in the bins that are sitting outside the store. I bet there are lots of delightful chemicals and dirt in them, just what that cake needs. Not to mention the chemicals that the fabric itself is treated with when it's manufactured.
If you want a burlap border don't use real fabric, make it out of fondant. If you have to use the real stuff, make some kind of barrier between that and the cake to make sure the fibers from the burlap don't get into the icing. Nobody wants to eat a mouthful of teeny hairs.
Kara Buntin owns A Cake To Remember LLC, custom wedding cakes in Richmond VA