The effort put into both baking and decorating the cakes made by home bakers themselves naturally leads to the need to protect it.
People dealing with cakes take extra precaution to feel more assured of the cake staying intact.
More care is taken of home baked goods when it is meant as a gift. Much attention and desire for a pleasing aesthetic for presentation of the cake is desired by home bakers.
The perception of what is "safe" for the cake is when the base is parallel to the ground.
Hence, to users, the cake is at risk of damage when it is not balanced.
Cakes are delicate and precious both to the gift-er and the receiver.