Yes, non-edible cakes made of light, cheap materials like styrofoam are routinely displayed at weddings and other ceremonies. One of the layers might be soft, allowing for fake-cake cutting.
The hosts know the cake is fake. Many of the guests know the cake is fake. After cake-cutting, the fake cake often remains on display while everyone eats slices of real cake brought in from a kitchen.
No effort is made to pretend that the cake on display is real. It has come to be understood, accepted, and expected by society that there should be a cheap sculpture of a cake on display and that everyone should act as if this cheap sculpture is a real cake during the ceremony.
The hosts know the cake is fake. Many of the guests know the cake is fake. After cake-cutting, the fake cake often remains on display while everyone eats slices of real cake brought in from a kitchen.
No effort is made to pretend that the cake on display is real. It has come to be understood, accepted, and expected by society that there should be a cheap sculpture of a cake on display and that everyone should act as if this cheap sculpture is a real cake during the ceremony.
How did we, as a society, arrive here?