I use pedestals under big three tiered cakes all the time. I royal ice the cake board to the pedestal and properly dowel the cake and I have never had an issue. :) Most of my customers like to use my pedestals for their own display purposes and I have delivered many a cake on Alaskan icy and hazardous roads without any mishap to date and that’s with me driving with one hand and holding the cake pedestal in the other. That or I have my husband drive and I just carry the cake directly on my lap.
-- Rachel, Fondant Flinger New Orleans, LA www.facebook.com/fondantflinger