I have a bride who wants a stacked three tiered white butter cream wedding cake with no borders. I have never done this before and I am concerned about how to hide the transition between each tier. I have always counted on the border or ribbon to hide it. This cake has no flowers just one piece of burlap and lace ribbon and a bow. The more I think about it the more I stress.

I saw a tutorial once where the lady made a small hollow in the buttercream of the bottom cake (only a very shallow one) to sit the above cake into so that the cake board actually sat in the icing rather than on top of it. I imagine that it would take a bit of practice to get right and that it may be easier to do touch ups / repairs with a non crusting buttercream. This might be worth looking into if you are worried about getting the cakes perfectly iced for traditional stacking.

I believe it was one of Ron Ben-Israel's videos where I saw him pipe a very small line of bc between the layers and then smooth it to cover the gap.  Like caulking a bath tub. It just disappeared.

I did this one with no borders, I had to work with a very cold cake to stack it so there were minimal boo-boos. It was a crusting cream cheese buttercream. I recall having to do a few touch ups but since the cake was cold it wasn't really an issue. In your case, the burlap and the ribbon I assume will be at the base of each tier so you should be ok.

I am asked for that occasionally.  I use IMBC.  I stack the previously refrigerated cakes at the venue, then pipe in a bead of BC to fill in the gaps and smooth with a small spatula or a finger.  if it's very cold, the warmth of your finger helps to smooth out the seam.  

She wants the burlap lace ribbon around the middle of the center tier.

Thank you everyone I will see if I can find a video.

Definitely! I don't like borders anyways, so I'm used to that. I will ice it on two boards: one the normal board, and that is set on a slightly larger board, and when its all done chilling, pop the cake off the bigger board, and voila! Perfect naked border.

I actually put together a tutorial on perfect bottom edges for fondant cakes, that you don't have to hide with a border. This will teach you how to get a completely seamless, free of ragged edges, flush bottom border that you won't want to cover with a border! And you don't need anything fancy to achieve it. :)

https://www.facebook.com/YumaCoutureCakes/app_251458316228

The only problem is she doesn't want fondant has to be butter cream.

AI described what I do in that situation earlier. I don't put borders on buttercream cakes either. If you level your cakes perfectly and cut your supports right, it's fine.