Scarlett873: you are correct, Disney only uses one brand of fondant. This is due to 2 reasons. One is the property wide initiative to eliminate trans fats from Disney offering, secondly is that the fondant used has been tested for appearance and workability.
BayouPrincess: you are correct as well. A layer of buttercream is applied to all cakes to insure a smooth surface for the fondant. Fondant can not be applied to a rough uniced surface,as it will magnify any imperfections.
Am

when the fondant is applied it is rolled out very thin, so when it is removed before cutting, it leaves the majority of the butter cream intact. The cakes are usually cut by the room captains, who are well versed in this procedure.
Caryndisneydiva: when the fondant is applied and served, it is a pliable surface, but it does not remain this way indefinately. As with any food product that is not wrapped, it will dry out within a short period of time. Your wedding topper was removed intact with the fondant in place, and boxed "to-go". Even in a box, the fondant will dry and become more solid.
29apr00: as stated above, when the fondant is removed, it is done carefully and with almost all of the butter cream in place. Presentation does not suffer. If anything, the removal of the fondant is the better of the 2 choices.
You appear to be familiar with cake construction, so I'm sure you know what kind of results come from attempting to cut a soft cake with a layer of fondant in place.
As the wedding cake warms at the reception, the underlying butter cream and fillings become softer than when they were removed from refrigeration. Most wedding cakes are displayed in the room for 4 hours before cutting.At the same time, the fondant is still, as you put it "gumlike". Even with a sharp knife, the fondant will stretch before the knife goes through it and crush the soft cake beneath.
To correctly cut a soft, fondant covered cake, the server must 1: dip a sharp knife in warm water,2, dry the knife with a clean towel, 3 cut the slice and plate it, 4 repeat the process. Imagine doing this for 200 guests. The wedding cake would need to be removed from the guests view at the start of the dinner service in order for it to be plated in time for dessert.
Also, many fondant cakes have layers of additional decorations on them. Draped effects, heavy piping, etc. Would you want these extra remnants on your plate? To me, this would appear "sloppy". I would rather eat cake then have to dissect these remains.
Fondants primary function is appearance. And while it is true that it is more costly, the effects done in fondant can not be done in butter cream. It is all a matter of the brides vision as to what her cake should look like.
Don't get caught up thinking you will waste the fondant if it isnt consumed. If your cake is the cake of your dreams, then the fondant has done it's job.